WILBERT

Wildauer Bücher+E-Medien Recherche-Tool

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • American Institute of Physics (AIP)  (154,867)
  • 1
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-09-08
    Description: Efficiency and dynamics of radiative recombination of carriers are crucial figures of merit for optoelectronic materials. Following the recent success of lead halide perovskites in efficient photovoltaic and light emitting technologies, here we review some of the noted literature on the luminescence of this emerging class of materials. After outlining the theoretical formalism that is currently used to explain the carrier recombination dynamics, we review a few significant works which use photoluminescence as a tool to understand and optimize the operation of perovskite based optoelectronic devices.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-09-17
    Description: Hybrid lead-halide perovskites have emerged as promising solution-processed semiconductor materials for thin-film optoelectronics. In this review, we discuss current challenges in perovskite LED performance, using thin-film and nano-crystalline perovskite as emitter layers, and look at device performance and stability. Fabrication of electrically pumped, optical-feedback devices with hybrid lead halide perovskites as gain medium is a future challenge, initiated by the demonstration of optically pumped lasing structures with low gain thresholds. We explain the material parameters affecting optical gain in perovskites and discuss the challenges towards electrically pumped perovskite lasers.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-09-28
    Description: Over the last few years, tremendous progress has been made in the research field of perovskite solar cells. Not only are record power conversion efficiencies now exceeding 20%, but our understanding about the different mechanisms leading to this extraordinary performance has improved phenomenally. The aim of this special issue is to review the current state-of-the-art understanding of perovskite solar cells. Most of the presented articles are research updates giving a succinct overview over different aspects concerning perovskite solar cells.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 4
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-10-04
    Description: The power conversion efficiency of lead halide perovskite solar cells recently surpassed 22.1%. In this study, we suggest the perovskite absorber growth mechanism of the two-step process could be explained by an Ostwald ripening growth model for planar-structure perovskite solar cells. We attempt to find out the source of two main problems such as unreacted PbI 2 and non-uniformed morphology by the proposed ripening growth mechanism and experimental results. This growth mechanism opens the way toward understanding a key aspect of the photovoltaic operation of high-efficiency, two-step perovskite solar cells.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 5
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-10-08
    Description: Metal nanoparticle-semiconductor interfaces are sites of complex light-matter interactions, in particular, the exciton-plasmon coupling which plays a key role in the optical response of such heterostructures. There exists a pathway of photoinduced charge transfer from the semiconductor to the metal, which can be used to controllably vary the driving forces at the interface that leads to tunable optoelectronic properties. In this letter, we report the observation of a dramatic suppression of plasmonic as well as excitonic absorption in a-Ge 24 Se 76 /gold nanoparticle heterostructures by trapped charges. Suppression of the excitonic absorption is strongly correlated with the plasmon wavelength.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 6
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-10-08
    Description: The elastocaloric effect in a columnar-grained Cu 71.5 Al 17.5 Mn 11 shape memory alloy fabricated by directional solidification was investigated. A large entropy change of 25.0 J/kg K generated by the reversible martensitic transformation was demonstrated. The adiabatic temperature change of 12-13 K was directly measured, covering a wide temperature range of more than 100 K. The low applied stress with a specific elastocaloric ability of 100.8 K/GPa was identified and the potentially attainable operational temperature window as wide as more than 215 K was also discussed. The outstanding elastocaloric refrigeration capability, together with the low applying stress and uniform phase transformation, makes the columnar-grained Cu–Al–Mn shape memory alloy a promising material for solid-state refrigeration.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 7
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-10-08
    Description: We report the growth of wafer-scale arrays of individually position-controlled and vertically aligned ZnO nanotube arrays on graphene deposited by chemical vapor deposition (CVD-graphene). Introducing two-dimensional layered materials such as graphene as a growth buffer has recently been suggested for growing nanomaterials on traditionally incompatible substrates. However, their growth has been restricted to small areas or had limited controllability. Here, we study the distinct growth behavior of ZnO on CVD-graphene that makes the selective area growth of individual nanostructures on its surface difficult, and propose a set of methods to overcome this. The resulting nanotube arrays, as examined by scanning electron microscopy and transmission electron microscopy, exhibited uniform morphologies and high structural quality over a large area and could be prepared on a broad variety of substrates, including amorphous, metallic, or flexible substrates.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 8
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-08-19
    Description: We have investigated the tunneling transport of mono- and few-layers of MnPS 3 by using conductive atomic force microscopy. Due to the band alignment of indium tin oxide/MnPS 3 /Pt-Ir tip junction, the key features of both Schottky junction and Fowler-Nordheim tunneling (FNT) were observed for all the samples with varying thickness. Using the FNT model and assuming the effective electron mass (0.5 m e ) of MnPS 3 , we estimate the tunneling barrier height to be 1.31 eV and the dielectric breakdown strength as 5.41 MV/cm.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 9
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-08-20
    Description: We report on synthesis and characterization of a new magnetic nanolaminate (V,Mn) 3 GaC 2 , which is the first magnetic MAX phase of a 312 stoichiometry. Atomically resolved energy dispersive X-ray mapping of epitaxial thin films reveals a tendency of alternate chemical ordering between V and Mn, with atomic layers composed of primarily one element only. Magnetometry measurements reveal a ferromagnetic response between 50 K and 300 K, with indication of a magnetic ordering temperature well above room temperature.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 10
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-08-20
    Description: Lead halide perovskite solar cells have shown a tremendous rise in power conversion efficiency with reported record efficiencies of over 20% making this material very promising as a low cost alternative to conventional inorganic solar cells. However, due to a differently severe “hysteretic” behaviour during current density-voltage measurements, which strongly depends on scan rate, device and measurement history, preparation method, device architecture, etc., commonly used solar cell measurements do not give reliable or even reproducible results. For the aspect of commercialization and the possibility to compare results of different devices among different laboratories, it is necessary to establish a measurement protocol which gives reproducible results. Therefore, we compare device characteristics derived from standard current density-voltage measurements with stabilized values obtained from an adaptive tracking of the maximum power point and the open circuit voltage as well as characteristics extracted from time resolved current density-voltage measurements. Our results provide insight into the challenges of a correct determination of device performance and propose a measurement protocol for a reliable characterisation which is easy to implement and has been tested on varying perovskite solar cells fabricated in different laboratories.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 11
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-08-23
    Description: Pb 0.9 La 0.1 (Zr 0.52 Ti 0.48 )O 3 (PLZT) relaxor-ferroelectric thin films were grown on SrRuO 3 /SrTiO 3 /Si substrates by pulsed laser deposition. A large recoverable storage density ( U reco ) of 13.7 J/cm 3 together with a high energy efficiency ( η ) of 88.2% under an applied electric field of 1000 kV/cm and at 1 kHz frequency was obtained in 300-nm-thick epitaxial PLZT thin films. These high values are due to the slim and asymmetric hysteresis loop when compared to the values in the reference undoped epitaxial lead zirconate titanate Pb(Zr 0.52 Ti 0.48 )O 3 ferroelectric thin films ( U reco = 9.2 J/cm 3 and η = 56.4%) which have a high remanent polarization and a small shift in the hysteresis loop, under the same electric field.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 12
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-08-24
    Description: Nanostructured Mn 3 Ge ribbons with a composition ranging from 77 to 74 at.% Mn were prepared using induction melting, melt-spinning, and subsequent heat treatment. The hard magnetic properties of the ribbons originate from the highly anisotropic tetragonal D 0 22 structure of Mn 3 Ge. Depending on the composition and the amount of ferrimagnetic Mn 5 Ge 2 as a secondary phase, a coercivity of up to μ 0 H C = 2.62 T was obtained for the Mn 3 Ge ribbons. Microstructure investigations by transmission electron microscopy confirmed the formation of the secondary phase. All samples show isotropic coercive fields, i.e., independent of the direction of the applied magnetic field in contrast to already known epitaxial thin films. The Curie temperature was found to be higher than 800 K, which is the temperature of the phase transition from the tetragonal D 0 22 structure to the hexagonal D 0 19 structure.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 13
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-08-30
    Description: Self-organized AlGaN nanowires by molecular beam epitaxy have attracted significant attention for deep ultraviolet optoelectronics. However, due to the strong compositional modulations under conventional nitrogen rich growth conditions, emission wavelengths less than 250 nm have remained inaccessible. Here we show that Al-rich AlGaN nanowires with much improved compositional uniformity can be achieved in a new growth paradigm, wherein a precise control on the optical bandgap of ternary AlGaN nanowires can be achieved by varying the substrate temperature. AlGaN nanowire LEDs, with emission wavelengths spanning from 236 to 280 nm, are also demonstrated.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 14
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-09-02
    Description: We present unusual high hardness (up to 7.7 GPa) achieved in Cu/Al multilayers relative to monolithic Cu and Al films (∼2 GPa and ∼1 GPa, respectively). Nanotwins and stacking faults (SFs) were proposed to be the main contributors of hardness enhancement, especially when h 〈 5 nm. Using molecular dynamics simulations of deposition, we demonstrated that intermixing near Cu/Al interface was paramount in stabilizing the SFs in both Cu and Al layers. Our experimental results indicated that the high strength caused by layer intermixing was in sharp contrast to the general belief that only sharp interface structures could strengthen the multilayers.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 15
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-09-02
    Description: The Co-Pt nanochessboard is a quasi-periodic, nanocomposite tiling of L1 0 and L1 2 magnetic phases that offers a novel structure for the investigation of exchange coupling, relevant to permanent magnet applications. Periodicity of the tiling is controlled by the rate of cooling through the eutectoid isotherm, resulting in control over the L1 0 -L1 2 exchange coupling. First order reversal curve analysis reveals a transition from partial coupling to nearly complete exchange-coupling in a Co 40.2 Pt 59.8 nanochessboard structured alloy as the periodicity is reduced below the critical correlation length. Micromagnetic simulations give insights into how exchange coupling manifests in the tiling, and its impact on microscopic magnetization reversal mechanisms.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 16
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-09-02
    Description: In this paper, an electrocaloric (EC) cooler prototype made of 150 ceramic-based Multi-Layer Capacitors (MLCs) has been detailed. This cooler involves a column of dielectric fluid where heat exchange with the MLCs takes place. The maximum variation of temperature in the fluid column due to the EC effect reaches 0.13 K whereas the heat exchanged during one stroke is 0.28 J. Although this prototype requires improvements with respect to heat exchange, the basic principle of creating a temperature gradient in a column of fluid has been validated.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 17
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-09-07
    Description: Perovskite solar cells (PSCs) marked tremendous progress in a short period of time and offer bright hopes for cheap solar electricity. Despite high power conversion efficiency 〉20%, its poor operational stability as well as involvement of toxic, volatile, and less-abundant materials hinders its practical deployment. The fact that degradation and toxicity are typically observed in the most successful perovskite involving organic cation and toxic lead, i.e., CH 3 NH 3 PbX 3 , requires a deep understanding of their role in photovoltaic performance in order to envisage if a non-toxic, stable yet highly efficient device is feasible. Towards this, we first provide an overview of the basic chemistry and physics of halide perovskites and its correlation with its extraordinary properties such as crystal structure, bandgap, ferroelectricity, and electronic transport. We then discuss device related aspects such as the various device designs in PSCs and role of interfaces in origin of PV parameters particularly open circuit voltage, various film processing methods and their effect on morphology and characteristics of perovskite films, and the origin and elimination of hysteresis and operational stability in these devices. We then identify future perspectives for stable and efficient PSCs for practical deployment.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 18
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-10-05
    Description: All-oxide photovoltaics could open rapidly scalable manufacturing routes, if only oxide materials with suitable electronic and optical properties were developed. SnO has exceptional doping and transport properties among oxides, but suffers from a strongly indirect band gap. Here, we address this shortcoming by band-structure engineering through isovalent but heterostructural alloying with divalent cations (Mg, Ca, Sr, and Zn). Using first-principles calculations, we show that suitable band gaps and optical properties close to that of direct semiconductors are achievable, while the comparatively small effective masses are preserved in the alloys. Initial thin film synthesis and characterization support the feasibility of the approach.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 19
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-10-05
    Description: The conventional mechanoluminescence (ML) mechanism of phosphors such as SrAl 2 O 4 :Eu and ZnS:Mn is known to utilize carrier trapping at shallow traps followed by stress (or strain)-induced detrapping, which leads to activator recombination in association with local piezoelectric fields. However, such a conventional ML mechanism was found to be invalid for the ZnS:Cu-embedded polydimethylsiloxane (PDMS) composite, due to the absence of luminescence with a rigid matrix and a negligibly small value of the piezoelectric coefficient (d 33 ) of the composite. An alternative mechanism, namely, the triboelectricity-induced luminescence has been proposed for the mechanically driven luminescence of a ZnS:Cu-PDMS composite.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 20
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-10-11
    Description: We used high-resolution Kelvin probe force microscopy (KPFM) to investigate the immobilization of a prostate specific antigen (PSA) antibody by measuring the surface potential (SP) on a MoS 2 surface over an extensive concentration range (1 pg/ml–100 μ g/ml). After PSA antibody immobilization, we demonstrated that the SP on the MoS 2 surface characterized by KPFM strongly correlated to the electrical signal of a MoS 2 bioFET. This demonstration can not only be used to optimize the immobilization conditions for captured molecules, but can also be applied as a diagnostic tool to complement the electrical detection of a MoS 2 FET biosensor.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 21
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-10-18
    Description: Direct conversion between thermal and electrical energy can be achieved by thermoelectric materials, which provide a viable route for power generation and solid state refrigeration. Here, we use a combination of energetic, electronic, and vibrational first-principles based results to predict the figure of merit performance in hole doped single crystals of SnS and (Pb,Sn)S. We find high ZT values for both materials, specifically for (Pb,Sn)S along the b -axis. Both SnS and (Pb,Sn)S have excellent power factors when doped, due to a combination of increased electrical conductivity (due to doping) and a significantly enhanced Seebeck coefficient obtained by a doping-induced multiband effect. Anharmonic phonon calculations combined with a Debye-Calloway model show that the lattice thermal conductivity of both compounds is low, due to intrinsic anharmonicity, and is lowered further by the random, solid solution nature of the cation sublattice of (Pb,Sn)S. (Pb,Sn)S exhibits a high ZT plateau ranging from 1.3 at 300 K to 1.9 at 800 K. The overall ZT of the hole doped (Pb,Sn)S crystals is predicted to outperform most of the current state-of-the-art thermoelectric sulfide materials.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 22
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-10-28
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 23
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-11-01
    Description: The temperature dependence of the thermal conductivity of 27 different single crystal oxides is reported from ≈20 K to 350 K. These crystals have been selected among the most common substrates for growing epitaxial thin-film oxides, spanning over a range of lattice parameters from ≈3.7 Å to ≈12.5 Å. Different contributions to the phonon relaxation time are discussed on the basis of the Debye model. This work provides a database for the selection of appropriate substrates for thin-film growth according to their desired thermal properties, for applications in which heat management is important.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 24
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-01-05
    Description: We report an in situ microbeam grazing incidence X-ray scattering study of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C 8 -BTBT) organic semiconductor thin film deposition by hollow pen writing. Multiple transient phases are observed during the crystallization for substrate temperatures up to ≈93 °C. The layered smectic liquid-crystalline phase of C 8 -BTBT initially forms and preceedes inter-layer ordering, followed by a transient crystalline phase for temperature 〉60 °C, and ultimately the stable phase. Based on these results, we demonstrate a method to produce extremely large grain size and high carrier mobility during high-speed processing. For high writing speed (25 mm/s), mobility up to 3.0 cm 2 /V-s has been observed.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 25
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-01-05
    Description: Transport characteristics of TiN/Ta/TaO x /TiN resistive-switching crossbar devices with amorphous TaO x functional layer have been investigated at cryogenic temperatures. Quasi-DC I - V characteristics at 10 K show a negative differential resistance region followed by a rapid transition to the non-volatile formed state. Accounting for Joule heating, the device temperature at the point of switching was estimated at 150 K. Measurements of transient resistance at low stage temperatures revealed an abrupt drop of resistance delayed by a characteristic incubation time after the leading edge of the voltage pulse. The incubation time was a strong function of applied voltage but did not depend on temperature between 10 K and 100 K. This implies a very low activation energy of the threshold switching process at low temperatures. Both of these observations argue against the involvement of oxygen vacancy motion at the onset of the forming process.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 26
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-01-13
    Description: A large remanent polarization close to theoretical value 80 μ C/cm 2 of bulk PbTiO 3 is achieved in epitaxial heterostructures of (120–600)-nm-thick PbTiO 3 films grown by pulsed laser deposition on (001) SrTiO 3 substrate using a 100-nm-thick SrRuO 3 bottom electrode layer. The heterostructures employing a 50-nm-thick electrode exhibit a significantly smaller polarization of ≤60 μ C/cm 2 . A detailed x-ray diffraction analysis of the crystal structure allows for relating this large polarization to electrode-controlled relaxation of epitaxial strain in PbTiO 3 . Based on the observed results, we anticipate that the electrode-promoted strain relaxation can be used to enhance polarization in other epitaxial ferroelectric films.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 27
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-01-29
    Description: High-mobility perovskite BaSnO 3 films are of significant interest as new wide bandgap semiconductors for power electronics, transparent conductors, and as high mobility channels for epitaxial integration with functional perovskites. Despite promising results for single crystals, high-mobility BaSnO 3 films have been challenging to grow. Here, we demonstrate a modified oxide molecular beam epitaxy (MBE) approach, which supplies pre-oxidized SnO x . This technique addresses issues in the MBE of ternary stannates related to volatile SnO formation and enables growth of epitaxial, stoichiometric BaSnO 3 . We demonstrate room temperature electron mobilities of 150 cm 2 V −1 s −1 in films grown on PrScO 3 . The results open up a wide range of opportunities for future electronic devices.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 28
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-02-02
    Description: We report the epitaxial growth and the mechanism of a higher temperature insulator-to-metal-transition (IMT) of vanadium dioxide (VO 2 ) thin films synthesized on aluminum nitride (AlN)/Si (111) substrates by a pulsed-laser-deposition method; the IMT temperature is T IMT ≈ 350 K. X-ray diffractometer and high resolution transmission electron microscope data show that the epitaxial relationship of VO 2 and AlN is VO 2 (010) ‖ AlN (0001) with VO 2 [101] ‖   AlN   [ 2 1 ̄ 1 ̄ 0 ] zone axes, which results in a substrate-induced tensile strain along the in-plane a and c axes of the insulating monoclinic VO 2 . This strain stabilizes the insulating phase of VO 2 and raises T IMT for 10 K higher than T IMT single crystal ≈ 340 K in a bulk VO 2 single crystal. Near T IMT , a resistance change of about four orders is observed in a thick film of ∼130 nm. The VO 2 /AlN/Si heterostructures are promising for the development of integrated IMT-Si technology, including thermal switchers, transistors, and other applications.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 29
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-02-02
    Description: The magnetocaloric effect in ferromagnetic single crystal EuTi 0.85 Nb 0.15 O 3 has been investigated using magnetization and heat capacity measurements. EuTi 0.85 Nb 0.15 O 3 undergoes a continuous ferromagnetic phase transition at T C = 9.5 K due to the long range ordering of magnetic moments of Eu 2+ (4 f 7 ). With the application of magnetic field, the spin entropy is strongly suppressed and a giant magnetic entropy change is observed near T C . The values of entropy change Δ S m and adiabatic temperature change Δ T ad are as high as 51.3 J kg −1 K −1 and 22 K, respectively, for a field change of 0–9 T. The corresponding magnetic heating/cooling capacity is 700 J kg −1 . This compound also shows large magnetocaloric effect even at low magnetic fields. In particular, the values of Δ S m reach 14.7 and 23.8 J kg −1 K −1 for field changes of 0–1 T and 0–2 T, respectively. The low-field giant magnetocaloric effect, together with the absence of thermal and field hysteresis makes EuTi 0.85 Nb 0.15 O 3 a very promising candidate for low temperature magnetic refrigeration.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 30
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-02-04
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 31
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-04-08
    Description: The underlying mechanism behind the blue/red color-switchable luminescence in the C 8 carbon quantum dots (CQDs)/organic hybrid light-emitting devices (LEDs) is investigated. The study shows that the increasing bias alters the energy-level spatial distribution and reduces the carrier potential barrier at the CQDs/organic layer interface, resulting in transition of the carrier transport mechanism from quantum tunneling to direct injection. This causes spatial shift of carrier recombination from the organic layer to the CQDs layer with resultant transition of electroluminescence from blue to red. By contrast, the pure CQDs-based LED exhibits green–red electroluminescence stemming from recombination of injected carriers in the CQDs.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 32
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-04-08
    Description: A key element of materials discovery and design is to learn from available data and prior knowledge to guide the next experiments or calculations in order to focus in on materials with targeted properties. We suggest that the tight coupling and feedback between experiments, theory and informatics demands a codesign approach, very reminiscent of computational codesign involving software and hardware in computer science. This requires dealing with a constrained optimization problem in which uncertainties are used to adaptively explore and exploit the predictions of a surrogate model to search the vast high dimensional space where the desired material may be found.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 33
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-04-08
    Description: Metal organic chemical vapor deposition of GaAs on standard nominal 300 mm Si(001) wafers was studied. Antiphase boundary (APB) free epitaxial GaAs films as thin as 150 nm were obtained. The APB-free films exhibit an improvement of the room temperature photoluminescence signal with an increase of the intensity of almost a factor 2.5. Hall effect measurements show an electron mobility enhancement from 200 to 2000 cm 2 /V s. The GaAs layers directly grown on industrial platform with no APBs are perfect candidates for being integrated as active layers for nanoelectronic as well as optoelectronic devices in a CMOS environment.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 34
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-04-12
    Description: Single crystals of Mott-Hubbard insulator LaVO 3 exhibit spin and orbital ordering along with a structural change below ≈140 K. The occurrence of orbital ordering in epitaxial LaVO 3 films has, however, been little investigated. By temperature-dependent Raman scattering spectroscopy, we probed and evidenced the transition to orbital ordering in epitaxial LaVO 3 film samples fabricated by pulsed-laser deposition. This opens up the possibility to explore the influence of different epitaxial strain (compressive vs . tensile) and of epitaxy-induced distortions of oxygen octahedra on the orbital ordering, in epitaxial perovskite vanadate films.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 35
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-04-12
    Description: The process of taking a new material from invention to deployment can take 20 years or more. Since the announcement of the Materials Genome Initiative in 2011, new attention has been paid to accelerating this timeframe to address key challenges in industries from energy, to biomedical materials, to catalysis, to polymers, particularly in the development of new materials discovery techniques. Materials informatics, or algorithmically analyzing materials data at scale to gain novel insight, has been lauded as a path forward in this regard. An equal challenge to discovery, however, is the acceleration from discovery to market. In this paper, we address application of an informatics approach to materials selection, manufacturing, and qualification and identify key opportunities and challenges in each of these areas with a focus on reducing time to market for new advanced materials technologies.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 36
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-04-22
    Description: Near infrared light emitting nanocrystals are known to lose efficiency when embedded in a polymer matrix. One of the factors leading to reduced efficiency is the labile nature of the ligands that may desorb off the nanocrystal surface when the nanocrystals are in the polymer solution. We show that adding trioctylphosphine to the nanocrystal-poly(methylmethacrylate) solution prior to film casting enhances the photoluminescence efficiency. The solid films’ photoluminescence quantum efficiency values are reduced by less than a factor of two in the solid form compared to the solution case. We demonstrate record efficiency values of 25% for lead sulfide nanocrystals solid films emitting at 1100 nm.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 37
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-04-26
    Description: This review focuses on the application of triblock copolymers as designed templates to synthesize nanoporous materials with various compositions. Asymmetric triblock copolymers have several advantages compared with symmetric triblock copolymers and diblock copolymers, because the presence of three distinct domains can provide more functional features to direct the resultant nanoporous materials. Here we clearly describe significant contributions of asymmetric triblock copolymers, especially polystyrene- block -poly(2-vinylpyridine)- block -poly(ethylene oxide) (abbreviated as PS- b -P2VP- b -PEO).
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 38
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-04-29
    Description: The creation of new materials “by design” is a process that starts from desired materials properties and proceeds to identify requirements for the constituent components. Such process is challenging because it inverts the typical modeling approach, which starts from given micro-level components to predict macro-level properties. We describe how to tackle this inverse problem using concepts from evolutionary computation. These concepts have widespread applicability and open up new opportunities for design as well as discovery. Here we apply them to design tasks involving two very different classes of soft materials, shape-optimized granular media and nanopatterned block copolymer thin films.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 39
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-05-14
    Description: Structural and optical properties of InGaAs quantum well fins (QWFs) selectively grown on Si using the aspect ratio trapping (ART) method in 200 nm deep SiO 2 trenches are studied. A new method combining cathodoluminescence, transmission electron microscopy, and precession electron diffraction techniques is developed to spatially correlate the presence of defects and/or strain with the light emission properties of a single InGaAs QWF. Luminescence losses and energy shifts observed at the nanoscale along InGaAs QWF are correlated with structural defects. We show that strain distortions measured around threading dislocations delimit both high and low luminescent areas. We also show that trapped dislocations on SiO 2 sidewalls can also result in additional distortions. Both behaviors affect optical properties of QWF at the nanoscale. Our study highlights the need to improve the ART growth method to allow integration of new efficient III-V optoelectronic components on Si.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 40
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-05-18
    Description: The electrocaloric effect (ECE) of two compositions (x = 0.06 and 0.07) of (1 − x)(Na 0.5 Bi 0.5 )TiO 3 -xKNbO 3 in the vicinity of the morphotropic phase boundary is studied by direct measurements. ΔT max = 1.5 K is measured at 125 °C under 70 kV/cm for NBT-6KN while ΔT max = 0.8 K is measured at 75 °C under 55 kV/cm for NBT-7KN. We show that the “shoulder,” T S , in the dielectric permittivity, marks the upper limit of the ECE peak under high applied electric fields. These results imply that the range of temperature with high ECE can be quickly identified for a given composition, which will significantly speed up the process of materials selection for ECE cooling.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 41
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-05-18
    Description: The influence of growth temperature on the surface morphology and luminescence properties of Eu-doped GaN layers grown by organometallic vapor phase epitaxy was investigated. By using a Eu source that does not contain oxygen in its molecular structure, and varying the growth temperature, the local defect environment around the Eu 3+ ions was manipulated, yielding a higher emission intensity from the Eu 3+ ions and a smoother sample surface. The optimal growth temperature was determined to be 960 °C and was used to fabricate a GaN-based red light-emitting diode with a significantly higher output power.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 42
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-05-20
    Description: Ferroelectrics are attractive candidate materials for environmentally friendly solid state refrigeration free of greenhouse gases. Their thermal response upon variations of external electric fields is largest in the vicinity of their phase transitions, which may occur near room temperature. The magnitude of the effect, however, is too small for useful cooling applications even when they are driven close to dielectric breakdown. Insight from microscopic theory is therefore needed to characterize materials and provide guiding principles to search for new ones with enhanced electrocaloric performance. Here, we derive from well-known microscopic models of ferroelectricity meaningful figures of merit for a wide class of ferroelectric materials. Such figures of merit provide insight into the relation between the strength of the effect and the characteristic interactions of ferroelectrics such as dipolar forces. We find that the long range nature of these interactions results in a small effect. A strategy is proposed to make it larger by shortening the correlation lengths of fluctuations of polarization. In addition, we bring into question other widely used but empirical figures of merit and facilitate understanding of the recently observed secondary broad peak in the electrocalorics of relaxor ferroelectrics.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 43
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-03-11
    Description: We demonstrate the selective fabrication of Ruddlesden-Popper (RP) type SrIrO 3 , Sr 3 Ir 2 O 7 , and Sr 2 IrO 4 epitaxial thin films from a single SrIrO 3 target using pulsed laser deposition (PLD). We identified that the growth conditions stabilizing each phase directly map onto the phase diagram expected from thermodynamic equilibria. This approach allows precise cation stoichiometry control as evidenced by the stabilization of single phase Sr 3 Ir 2 O 7 for the first time, overcoming the close thermodynamic stability between neighboring RP phases. Despite the non-equilibrium nature of PLD, these results highlight the importance of thermodynamic guiding principles to strategically synthesize the targeted phase in complex oxide thin films.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 44
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-03-11
    Description: We established a process for growing highly ordered MoS 2 thin films. The process consists of four steps: MoO 3 thermal evaporation, first annealing, sulfurization, and second annealing. The main feature of this process is that thermally deposited MoO 3 thin films are employed as a precursor for the MoS 2 films. The first deposition step enabled us to achieve precise control of the resulting thickness of the MoS 2 films with high uniformity. The crystalline structures, surface morphologies, and chemical states at each step were characterized by X-ray diffraction, atomic force microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. Based on these characterizations and a careful optimization of the growth conditions, we successfully produced a highly oriented MoS 2 thin film with a thickness of five monolayers over an entire one-centimeter-square sapphire substrate.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 45
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-03-17
    Description: Electrical manipulation of magnetism has been a long sought-after goal to realize energy-efficient spintronics. During the past decade, multiferroic materials combining (anti)ferromagnetic and ferroelectric properties are now drawing much attention and many reports have focused on magnetoelectric coupling effect through strain, charge, or exchange bias. This paper gives an overview of recent progress on electrical manipulation of magnetism through strain-mediated magnetoelectric coupling in multiferroic heterostructures.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 46
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-03-19
    Description: Thin films of homogeneous mixture of amorphous silicon and aluminum were produced with magnetron sputtering using 2-phase Al–Si targets. The films exhibited variable compositions, with and without the presence of hydrogen, aSi 1− x Al x and aSi 1− x Al x H y . The structure and optical properties of the films were investigated using transmission electron microscopy, X-ray photoelectron spectroscopy, UV-Vis NIR spectrometry, ellipsometry, and atomistic modeling. We studied the effect of alloying aSi with Al (within the range 0–25 at. %) on the optical band gap, refractive index, transmission, and absorption. Alloying aSi with Al resulted in a non-transparent film with a low band gap ( 1 eV. Variations of the Al and hydrogen content allowed for tuning of the optoelectronic properties. The films are stable up to a temperature of 300 °C. At this temperature, we observed Al induced crystallization of the amorphous silicon and the presence of large Al particles in a crystalline Si matrix.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 47
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-03-29
    Description: Two structural phase transitions are investigated in highly strained BiFeO 3 thin films as a function of film thickness and temperature via synchrotron x-ray diffraction. Both transition temperatures (upon heating: monoclinic M C to monoclinic M A to tetragonal) decrease as the film becomes thinner. A film-substrate interface layer, evidenced by half-order peaks, contributes to this behavior, but at larger thicknesses (above a few nanometers), the temperature dependence results from electrostatic considerations akin to size effects in ferroelectric phase transitions, but observed here for structural phase transitions within the ferroelectric phase. For ultra-thin films, the tetragonal structure is stable to low temperatures.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 48
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-03-16
    Description: Organic-inorganic halide perovskites, especially methylammonium lead halide, have recently led to remarkable advances in photovoltaic devices. However, due to environmental and stability concerns around the use of lead, research into lead-free perovskite structures has been attracting increasing attention. In this study, a layered perovskite-like architecture, (NH 4 ) 3 Bi 2 I 9 , is prepared from solution and the structure solved by single crystal X-ray diffraction. The band gap, which is estimated to be 2.04 eV using UV-visible spectroscopy, is lower than that of CH 3 NH 3 PbBr 3 . The energy-minimized structure obtained from first principles calculations is in excellent agreement with the X-ray results and establishes the locations of the hydrogen atoms. The calculations also point to a significant lone pair effect on the bismuth ion. Single crystal and powder conductivity measurements are performed to examine the potential application of (NH 4 ) 3 Bi 2 I 9 as an alternative to the lead containing perovskites.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 49
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-03-23
    Description: The magnetic and transport properties of Fe 3 O 4 films with a series of thicknesses are investigated. For the films with thickness below 15 nm, the saturation magnetization (M s ) increases and the coercivity decreases with the decrease in films’ thickness. The M s of 3 nm Fe 3 O 4 film is dramatically increased to 1017 emu/cm 3 . As for films’ thickness more than 15 nm, M s is tending to be close to the Fe 3 O 4 bulk value. Furthermore, the Verwey transition temperature (T v ) is visible for all the films, but suppressed for 3 nm film. We also find that the ρ of 3 nm film is the highest of all the films. The suppressed T v and high ρ may be related to the islands morphology in 3 nm film. To study the structure, magnetic, and transport properties of the Fe 3 O 4 films, we propose that the giant magnetic moment most likely comes from the spin of Fe ions in the tetrahedron site switching parallel to the Fe ions in the octahedron site at the surface, interface, and grain boundaries. The above results are of great significance and also provide a promising future for either device applications or fundamental research.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 50
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-04-08
    Description: Mn 0.05 Ge 0.95 quantum dots (QDs) samples were grown by molecular beam epitaxy on Si substrates and 15-nm-thick fully strained Si 0.8 Ge 0.2 virtual substrates, respectively. The QDs samples grown on the Si 0.8 Ge 0.2 virtual substrates show a significant ferromagnetism with a Curie temperature of 227 K, while the QDs samples grown on the Si substrates are non-ferromagnetic. Microstructures of the QDs samples were characterized by high resolution transmission electron microscopy and synchrotron radiation X-ray diffraction. Interdependence between microstructure and ferromagnetism of Mn-doped Ge QDs was investigated. For the QDs sample grown on the strained Si 0.8 Ge 0.2 virtual substrate, although the ferromagnetic phase Mn 5 Ge 3 clusters were found to be formed in small dome-shaped dots, the significant ferromagnetism observed in that sample is attributed to ferromagnetic phase Mn-doped large dome-shaped Ge QDs, rather than to the ferromagnetic phase Mn 5 Ge 3 clusters. The fully strained Si 0.8 Ge 0.2 virtual substrates would result in a residual strain into the QDs and an increase in Ge composition in the QDs. Both consequences favor the formations of ferromagnetic phase Mn-doped Ge QDs from points of view of quantum confinement effect as well as Mn doping at substitutional sites.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 51
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-04-13
    Description: This letter reports on a systematic investigation of sputter induced damage in graphene caused by low energy Ar + ion bombardment. The integral numbers of ions per area (dose) as well as their energies are varied in the range of a few eV’s up to 200 eV. The defects in the graphene are correlated to the dose/energy and different mechanisms for the defect formation are presented. The energetic bombardment associated with the conventional sputter deposition process is typically in the investigated energy range. However, during sputter deposition on graphene, the energetic particle bombardment potentially disrupts the crystallinity and consequently deteriorates its properties. One purpose with the present study is therefore to demonstrate the limits and possibilities with sputter deposition of thin films on graphene and to identify energy levels necessary to obtain defect free graphene during the sputter deposition process. Another purpose is to disclose the fundamental mechanisms responsible for defect formation in graphene for the studied energy range.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 52
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-04-15
    Description: We report the magnetic and optical properties of CuCr 2 O 4 thin films fabricated by atomic layer deposition (ALD) from Cu(thd) 2 , Cr(acac) 3 , and ozone; we deposit 200 nm thick films and anneal them at 700 °C in oxygen atmosphere to crystallize the spinel phase. A ferrimagnetic transition at 140 K and a direct bandgap of 1.36 eV are determined for the films from magnetic and UV-vis spectrophotometric measurements. Electrical transport measurements confirm the p-type semiconducting behavior of the films. As the ALD technique allows the deposition of conformal pin-hole-free coatings on complex 3D surfaces, our CuCr 2 O 4 films are interesting material candidates for various frontier applications.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 53
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-02-09
    Description: Structural and transport properties in the normal and superconducting states are investigated in a Ca 0.8 La 0.2 FeAs 2 single crystal with T c = 27 K, belonging to the newly discovered 112 family of iron based superconductors. The transport critical current density J c for both field directions measured in a focused ion beam patterned microbridge reveals a weakly field dependent and low anisotropic behaviour with a low temperature value as high as J c (B = 0) ∼ 10 5 A/cm 2 . This demonstrates not only bulk superconductivity but also the potential of 112 superconductors towards applications. Interestingly, this superconducting compound undergoes a structural transition below 100 K which is evidenced by temperature-dependent X-ray diffraction measurements. Data analysis of Hall resistance and magnetoresistivity indicate that magnetotransport properties are largely dominated by an electron band, with a change of regime observed in correspondence of the onset of a structural transition. In the low temperature regime, the contribution of a hole band to transport is suggested, possibly playing a role in determining the superconducting state.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 54
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-02-13
    Description: We discuss and present search strategies for finding new thermoelectric compositions based on first principles electronic structure and transport calculations. We illustrate them by application to a search for potential n -type oxide thermoelectric materials. This includes a screen based on visualization of electronic energy isosurfaces. We report compounds that show potential as thermoelectric materials along with detailed properties, including SrTiO 3 , which is a known thermoelectric, and appropriately doped KNbO 3 and rutile TiO 2 .
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 55
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-01-05
    Description: For use in high-magnetic-field coil-based applications, the critical current density ( J c ) of REBa 2 Cu 3 O y (REBCO, where RE = rare earth) coated conductors must be isotropically improved, with respect to the direction of the magnetic field; these improvements must be realized at the operating conditions of these applications. In this study, improvement of the J c for various applied directions of magnetic field was achieved by controlling the morphology of the BaHfO 3 (BHO) nano-rods in a SmBCO film. We fabricated the 3.0 vol. % BHO-doped SmBCO film at a low growth temperature of 720 °C, by using a seed layer technique ( T s = 720 °C film). The low-temperature growth resulted in a morphological change in the BHO nano-rods. In fact, a high number density of (3.1 ± 0.1) × 10 3 μ m −2 of small (diameter: 4 ± 1 nm), discontinuous nano-rods that grew in various directions, was obtained. In J c measurements, the J c of the T s = 720 °C film in all directions of the applied magnetic field was higher than that of the non-doped SmBCO film. The J c min (6.4 MA/cm 2 ) of the former was more than 6 times higher than that (1.0 MA/cm 2 ) of the latter at 40 K, under 3 T. The aforementioned results indicated that the discontinuous BHO nano-rods, which occurred with a high number density, exerted a 3D-like flux pinning at the measurement conditions considered. Moreover, at 4.2 K and under 17 T, a flux pinning force density of 1.6 TN/m 3 was realized; this value was comparable to the highest value recorded, to date.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 56
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-01-21
    Description: We calculate the critical thickness for misfit dislocation (MD) formation in lattice mismatched semipolar and nonpolar III-nitride wurtzite semiconductor layers for the case of MDs originated from prismatic slip (PSMDs). It has been shown that there is a switch of stress relaxation modes from generation of basal slip originated MDs to PSMDs after the angle between c -axis in wurtzite crystal structure and the direction of semipolar growth reaches a particular value, e.g., ∼70° for Al 0.13 Ga 0.87 N/GaN ( h 0 h ̄ 1 ) semipolar heterostructures. This means that for some semipolar growth orientations of III-nitride heterostructures biaxial relaxation of misfit stress can be realized. The results of modeling are compared to experimental data on the onset of plastic relaxation in Al x Ga 1−x N/GaN heterostructures.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 57
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-04-29
    Description: The global trend of miniaturization and concomitant increase of functionality in microelectronics, microoptics, and various other fields in microtechnology leads to an emerging demand for temperature control at small scales. In this realm, elastocaloric cooling is an interesting alternative to thermoelectrics due to the large latent heat and good down-scaling behavior. Here, we investigate the elastocaloric effect due to a stress-induced phase transformation in binary TiNi and quaternary TiNiCuCo films of 20 μ m thickness produced by DC magnetron sputtering. The mesoscale mechanical and thermal performance, as well as the fatigue behavior are studied by uniaxial tensile tests combined with infrared thermography and digital image correlation measurements. Binary films exhibit strong features of fatigue, involving a transition from Lüders-like to homogeneous transformation behavior within three superelastic cycles. Quaternary films, in contrast, show stable Lüders-like transformation without any signs of degradation. The elastocaloric temperature change under adiabatic conditions is −15 K and −12 K for TiNi and TiNiCuCo films, respectively. First-of-its-kind heat pump demonstrators are developed that make use of out-of-plane deflection of film bridges. Owing to their large surface-to-volume ratio, the demonstrators reveal rapid heat transfer. The TiNiCuCo-based devices, for instance, generate a temperature difference of 3.5 K within 13 s. The coefficients of performance of the demonstrators are about 3.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 58
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-05-14
    Description: Materials informatics owes much to bioinformatics and the Materials Genome Initiative has been inspired by the Human Genome Project. But there is more to bioinformatics than genomes, and the same is true for materials informatics. Here we describe the rapidly expanding role of searching for structures of materials using first-principles electronic-structure methods. Structure searching has played an important part in unraveling structures of dense hydrogen and in identifying the record-high-temperature superconducting component in hydrogen sulfide at high pressures. We suggest that first-principles structure searching has already demonstrated its ability to determine structures of a wide range of materials and that it will play a central and increasing part in materials discovery and design.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 59
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-05-14
    Description: The tailoring of molecular weight distribution and the functional group density of vinyl-terminated polydimethylsiloxane (PDMS) by molecular beam deposition is demonstrated herein. Thermally evaporated PDMS and its residue are characterized using gel permeation chromatography and nuclear magnetic resonance. Thermal fragmentation of vinyl groups occurs for evaporation temperatures above 487 K (214 °C). At a background pressure of 10 −6 mbar, the maximum molecular weight distribution is adjusted from (700 ± 100) g/mol to (6100 ± 100) g/mol with a polydispersity index of 1.06 ± 0.02. The content of vinyl-termination per repeating unit of PDMS is tailored from (2.8 ± 0.2)% to (5.6 ± 0.1)%. Molecular weights of vinyl-terminated PDMS evaporated at temperatures above 388 K (115 °C) correspond to those attributed to trimethyl-terminated PDMS. Side groups of linear PDMS dominate intermolecular interactions and vapor pressure.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 60
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-05-17
    Description: In this contribution, we demonstrate the optimization of the microstructures of the Pb 0.85 La 0.1 (Zr 0.65 Ti 0.35 )O 3 (PLZT) relaxor ferroelectric ceramics and subsequent enhancements in their polarization and electrical resistivity by using a hot-pressing process. The resulting superior breakdown strength of hot-pressed PLZT enables the application of high electric field to induce a giant electrocaloric effect, in which the adiabatic change of temperature (Δ T ) and the isothermal change of entropy (Δ S ) are around 2 times greater than those of the samples prepared by the conventional sintering approach using muffle furnace. Moreover, the addition of extra PbO to make up the loss of Pb in the high-temperature sintering leads to the further improvements in the phase composition and electrical properties of PLZT, due to inhibition of the pyrochlore phase formation. The relationship among the sintering conditions, the content of excess PbO, and the microstructure as well as the electrical characteristics of PLZT have been investigated in a systematic manner. This work provides a facile approach to enhanced electrocaloric effect in bulk ceramics.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 61
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-05-27
    Description: Synthesis of inorganic extended solids is a critical starting point from which real-world functional materials and their consequent technologies originate. However, unlike the rich mechanistic foundation of organic synthesis, with its underlying rules of assembly (e.g., functional groups and their reactivities), the synthesis of inorganic materials lacks an underpinning of such robust organizing principles. In the latter case, any such rules must account for the diversity of chemical species and bonding motifs inherent to inorganic materials and the potential impact of mass transport on kinetics, among other considerations. Without such assembly rules, there is less understanding, less predictive power, and ultimately less control of properties. Despite such hurdles, developing a mechanistic understanding for synthesis of inorganic extended solids would dramatically impact the range of new material discoveries and resulting new functionalities, warranting a broad call to explore what is possible. Here we discuss our recent approaches toward a mechanistic framework for the synthesis of bulk inorganic extended solids, in which either embryonic atomic correlations or fully developed phases in solutions or melts can be identified and tracked during product selection and crystallization. The approach hinges on the application of high-energy x-rays, with their penetrating power and large Q-range, to explore reaction pathways in situ . We illustrate this process using two examples: directed assembly of Zr clusters in aqueous solution and total phase awareness during crystallization from K–Cu–S melts. These examples provide a glimpse of what we see as a larger vision, in which large scale simulations, data-driven science, and in situ studies of atomic correlations combine to accelerate materials discovery and synthesis, based on the assembly of well-defined, prenucleated atomic correlations.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 62
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-03-30
    Description: Searchable, interactive, databases of material properties, particularly those relating to functional materials (magnetics, thermoelectrics, photovoltaics, etc.) are curiously missing from discussions of machine-learning and other data-driven methods for advancing new materials discovery. Here we discuss the manual aggregation of experimental data from the published literature for the creation of interactive databases that allow the original experimental data as well additional metadata to be visualized in an interactive manner. The databases described involve materials for thermoelectric energy conversion, and for the electrodes of Li-ion batteries. The data can be subject to machine-learning, accelerating the discovery of new materials.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 63
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-04-01
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 64
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-04-01
    Description: The dynamics of a magnetic domain wall (DW) under a transverse magnetic field H y are investigated in two-dimensional (2D) Co/Ni microstrips, where an interfacial Dzyaloshinskii-Moriya interaction (DMI) exists with DMI vector D lying in + y direction. The DW velocity exhibits asymmetric behavior for ± H y ; that is, the DW velocity becomes faster when H y is applied antiparallel to D . The key experimental results are reproduced in a 2D micromagnetic simulation, which reveals that the interfacial DMI suppresses the periodic change of the average DW angle φ even above the Walker breakdown and that H y changes φ , resulting in a velocity asymmetry. This suggests that the 2D DW motion, despite its microscopic complexity, simply depends on the average angle of the DW and thus can be described using a one-dimensional soliton model. These findings provide insight into the magnetic DW dynamics in 2D systems, which are important for emerging spin-orbitronic applications.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 65
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-04-14
    Description: In artificial multiferroics hybrids consisting of ferromagnetic La 0.7 Sr 0.3 MnO 3 (LSMO) and ferroelectric BaTiO 3 epitaxial layers, net Ti moments are found from polarized resonant soft x-ray reflectivity and absorption. The Ti dichroic reflectivity follows the Mn signal during the magnetization reversal, indicating exchange coupling between the Ti and Mn ions. However, the Ti dichroic reflectivity shows stronger temperature dependence than the Mn dichroic signal. Besides a reduced ferromagnetic exchange coupling in the interfacial LSMO layer, this may also be attributed to a weak Ti-Mn exchange coupling that is insufficient to overcome the thermal energy at elevated temperatures.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 66
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-04-16
    Description: Our ability to collect “big data” has greatly surpassed our capability to analyze it, underscoring the emergence of the fourth paradigm of science, which is data-driven discovery. The need for data informatics is also emphasized by the Materials Genome Initiative (MGI), further boosting the emerging field of materials informatics. In this article, we look at how data-driven techniques are playing a big role in deciphering processing-structure-property-performance relationships in materials, with illustrative examples of both forward models (property prediction) and inverse models (materials discovery). Such analytics can significantly reduce time-to-insight and accelerate cost-effective materials discovery, which is the goal of MGI.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 67
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-04-21
    Description: In this paper, intrinsic and extrinsic factors dependent switching process in P(VDF-TrFE) thin films is investigated through time domain polarization measurements. The thinning-induced increase of switching time is observed for samples below 80 nm due to the surface oxide layer. For thinner samples the switchable polarization decreases with decreasing temperature since domain pinning prevails. Switching is faster using metal electrode with higher work function, which can be attributed to the lower depolarization field. Furthermore, the switching time increases with increasing the waiting time and increasing the pulse width of the prepolarization pulse caused by imprint effect.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 68
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-04-30
    Description: Single nanowires of two manganese oxide polymorphs (α-MnO 2 and todorokite manganese oxide), which display a controlled size variation in terms of their square structural tunnels, were isolated onto nanofabricated platforms using dielectrophoresis. This platform allowed for the measurement of the electronic conductivity of these manganese oxides, which was found to be higher in α-MnO 2 as compared to that of the todorokite phase by a factor of ∼46. Despite this observation of substantially higher electronic conductivity in α-MnO 2 , the todorokite manganese oxide exhibited better electrochemical rate performance as a Li-ion battery cathode. The relationship between this electrochemical performance, the electronic conductivities of the manganese oxides, and their reported ionic conductivities is discussed for the first time, clearly revealing that the rate performance of these materials is limited by their Li + diffusivity, and not by their electronic conductivity. This result reveals important new insights relevant for improving the power density of manganese oxides, which have shown promise as a low-cost, abundant, and safe alternative for next-generation cathode materials. Furthermore, the presented experimental approach is suitable for assessing a broader family of one-dimensional electrode active materials (in terms of their electronic and ionic conductivities) for both Li-ion batteries and for electrochemical systems utilizing charge-carrying ions beyond Li + .
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 69
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-02-13
    Description: Through empirical observations, sodium (Na) has been identified as a benign contaminant in some thin-film solar cells. Here, we intentionally contaminate thermally evaporated tin sulfide (SnS) thin-films with sodium and measure the SnS absorber properties and solar cell characteristics. The carrier concentration increases from 2 × 10 16 cm −3 to 4.3 × 10 17 cm −3 in Na-doped SnS thin-films, when using a 13 nm NaCl seed layer, which is detrimental for SnS photovoltaic applications but could make Na-doped SnS an attractive candidate in thermoelectrics. The observed trend in carrier concentration is in good agreement with density functional theory calculations, which predict an acceptor-type Na Sn defect with low formation energy.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 70
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-02-19
    Description: The past decade has been especially creative for spintronics since the (re)discovery of various two dimensional (2D) materials. Due to the unusual physical characteristics, 2D materials have provided new platforms to probe the spin interaction with other degrees of freedom for electrons, as well as to be used for novel spintronics applications. This review briefly presents the most important recent and ongoing research for spintronics in 2D materials.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 71
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-02-25
    Description: Solution processable semiconductor oxides have opened a new paradigm for the enhancement of the lifetime of thin film solar cells. Their fabrication by low-cost and environmentally friendly solution-processable methods makes them ideal barrier (hole and electron) transport layers. In this work, we fabricate flexible ITO-free organic solar cells (OPV) by printing methods applying an aqueous solution-processed V 2 O 5 as the hole transport layer (HTL) and compared them to devices applying PEDOT:PSS. The transparent conducting electrode was PET/Ag/PEDOT/ZnO, and the OPV configuration was PET/Ag/PEDOT/ZnO/P3HT:PC 60 BM/HTL/Ag. Outdoor stability analyses carried out for more than 900 h revealed higher stability for devices fabricated with the aqueous solution-processed V 2 O 5 .
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 72
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-02-25
    Description: Electric field control of magnetization and anisotropy in layered structures with perpendicular magnetic anisotropy is expected to increase the versatility of spintronic devices. As a model system for reversible voltage induced changes of magnetism by magnetoionic effects, we present several oxide/metal heterostructures polarized in an electrolyte. Room temperature magnetization of Fe-O/Fe layers can be changed by 64% when applying only a few volts in 1M KOH. In a next step, the bottom interface of the in-plane magnetized Fe layer is functionalized by an L1 0 FePt(001) underlayer exhibiting perpendicular magnetic anisotropy. During subsequent electrocrystallization and electrooxidation, well defined epitaxial Fe 3 O 4 /Fe/FePt heterostructures evolve. The application of different voltages leads to a thickness change of the Fe layer sandwiched between Fe-O and FePt. At the point of transition between rigid magnet and exchange spring magnet regime for the Fe/FePt bilayer, this induces a large variation of magnetic anisotropy.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 73
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-02-25
    Description: We discuss growth and magnetic properties of high-quality two dimensional (2D) Sn 1−x Mn x Se 2 films. Thin films of this 2D ternary alloy with a wide range of Mn concentrations were successfully grown by molecular beam epitaxy. Mn concentrations up to x ≈ 0.60 were achieved without destroying the crystal structure of the parent SnSe 2 2D system. Most important, the specimens show clear weak ferromagnetic behavior above room temperature, which should be of interest for 2D spintronic applications.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 74
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-03-02
    Description: The magnetoelectric effects are investigated in a cubic compound SrCuTe 2 O 6 , in which uniform Cu 2+ ( S = 1/2) spin chains with considerable spin frustration exhibit a concomitant antiferromagnetic transition and dielectric constant peak at T N ≈ 5.5 K. Pyroelectric J p ( T ) and magnetoelectric current J ME ( H ) measurements in the presence of a bias electric field are used to reveal that SrCuTe 2 O 6 shows clear variations of J p ( T ) across T N at constant magnetic fields. Furthermore, isothermal measurements of J ME ( H ) also develop clear peaks at finite magnetic fields, of which traces are consistent with the spin-flop transitions observed in the magnetization studies. As a result, the anomalies observed in J p ( T ) and J ME ( H ) curves match well with the field-temperature phase diagram constructed from magnetization and dielectric constant measurements, demonstrating that SrCuTe 2 O 6 is a new magnetoelectric compound with S = 1/2 spin chains.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 75
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-03-02
    Description: We report the experimental observation of longitudinal spin Seebeck effect in a multiferroic helimagnet Ba 0.5 Sr 1.5 Zn 2 Fe 12 O 22 . Temperature gradient applied normal to Ba 0.5 Sr 1.5 Zn 2 Fe 12 O 22 /Pt interface generates inverse spin Hall voltage of spin current origin in Pt, whose magnitude was found to be proportional to bulk magnetization of Ba 0.5 Sr 1.5 Zn 2 Fe 12 O 22 even through the successive magnetic transitions among various helimagnetic and ferrimagnetic phases. This finding demonstrates that the helimagnetic spin wave can be an effective carrier of spin current. By controlling the population ratio of spin-helicity domains characterized by clockwise/counter-clockwise manner of spin rotation with use of poling electric field in the ferroelectric helimagnetic phase, we found that spin-helicity domain distribution does not affect the magnitude of spin current injected into Pt. The results suggest that the spin-wave spin current is rather robust against the spin-helicity domain wall, unlike the case with the conventional ferromagnetic domain wall.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 76
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-03-10
    Description: Magnetocaloric materials are promising as solid state refrigerants for more efficient and environmentally friendly cooling devices. The highest effects have been observed in materials that exhibit a first-order phase transition. These transformations proceed by nucleation and growth which lead to a hysteresis. Such irreversible processes are undesired since they heat up the material and reduce the efficiency of any cooling application. In this article, we demonstrate an approach to decrease the hysteresis by locally changing the nucleation barrier. We created artificial nucleation sites and analyzed the nucleation and growth processes in their proximity. We use Ni-Mn-Ga, a shape memory alloy that exhibits a martensitic transformation. Epitaxial films serve as a model system, but their high surface-to-volume ratio also allows for a fast heat transfer which is beneficial for a magnetocaloric regenerator geometry. Nanoindentation is used to create a well-defined defect. We quantify the austenite phase fraction in its proximity as a function of temperature which allows us to determine the influence of the defect on the transformation.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 77
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-05-19
    Description: A multilayer capacitor comprising 19 layers of 38 μ m-thick 0.9Pb(Mg 1/3 Nb 2/3 )O 3 –0.1PbTiO 3 has elsewhere been shown to display electrocaloric temperature changes of 2.2 K due to field changes of 24 V μ m −1 , near ∼100 °C. Here we demonstrate temperature changes of 1.2 K in an equivalent device with 2.6 times the thermal mass, i.e., 49 layers that could tolerate 10.3 V μ m −1 . Breakdown was compromised by the increased number of layers, and occurred at 10.5 V μ m −1 near the edge of a near-surface inner electrode. Further optimization is required to improve the breakdown strength of large electrocaloric multilayer capacitors for cooling applications.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 78
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-05-19
    Description: To experimentally (dis)prove ferroelectric effects on the properties of lead-halide perovskites and of solar cells, based on them, we used second-harmonic-generation spectroscopy and the periodic temperature change (Chynoweth) technique to detect the polar nature of methylammonium lead bromide (MAPbBr 3 ). We find that MAPbBr 3 is probably centrosymmetric and definitely non-polar; thus, it cannot be ferroelectric. Whenever pyroelectric-like signals were detected, they could be shown to be due to trapped charges, likely at the interface between the metal electrode and the MAPbBr 3 semiconductor. These results indicate that the ferroelectric effects do not affect steady-state performance of MAPbBr 3 solar cells.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 79
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-05-21
    Description: PbSe is an inexpensive alternative for PbTe as a mid-temperature thermoelectric material, but few investigations have been reported about its intrinsic properties despite recent efforts on doping techniques. In this work, pristine PbSe bulk materials were synthesized by a process combining mechanical alloying and spark plasma sintering, which is increasingly used for processing thermoelectric materials, and their electrical and thermal transport properties as well as thermoelectric performance were investigated in a wide temperature range. A maximum ZT ∼0.83 was obtained at 673 K in nominal composition PbSe + 3 or 4 at. % Pb, leading to nearly 50% enhancement from reported n -type pristine PbSe, mainly benefitting from the improved electrical performance. Furthermore, the potential thermoelectric efficiency was also improved due to the enhanced low-temperature performance, showing a high average ZT of 0.6 that is even comparable to that of commercial n -type Bi 2 Te 3 materials.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 80
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-05-21
    Description: In this letter, we report a NiAl buffer layer as a template for the integration of epitaxial current-perpendicular-plane-giant magnetoresistive (CPP-GMR) devices on a Si(001) single crystalline substrate. By depositing NiAl on a Si wafer at an elevated temperature of 500 °C, a smooth and epitaxial B 2-type NiAl(001) layer was obtained. The surface roughness was further improved by depositing Ag on the NiAl layer and applying subsequent annealing process. The epitaxial CPP-GMR devices grown on the buffered Si(001) substrate present a large magnetoresistive output comparable with that of the devices grown on an MgO(001) substrate, demonstrating the possibility of epitaxial spintronic devices with a NiAl templated Si wafer for practical applications.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 81
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-05-24
    Description: We report a systematic study on the thermoelectric performance of spin Seebeck devices based on Fe 3 O 4 /Pt junction systems. We explore two types of device geometries: a spin Hall thermopile and spin Seebeck multilayer structures. The spin Hall thermopile increases the sensitivity of the spin Seebeck effect, while the increase in the sample internal resistance has a detrimental effect on the output power. We found that the spin Seebeck multilayers can overcome this limitation since the multilayers exhibit the enhancement of the thermoelectric voltage and the reduction of the internal resistance simultaneously, therefore resulting in significant power enhancement. This result demonstrates that the multilayer structures are useful for improving the thermoelectric performance of the spin Seebeck effect.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 82
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-06-02
    Description: Bi 2 Te 3 -based compounds are a well-known class of outstanding thermoelectric materials. β-As 2 Te 3 , another member of this family, exhibits promising thermoelectric properties around 400 K when appropriately doped. Herein, we investigate the high-temperature thermoelectric properties of the β-As 2− x Bi x Te 3 solid solution. Powder X-ray diffraction and scanning electron microscopy experiments showed that a solid solution only exists up to x = 0.035. We found that substituting Bi for As has a beneficial influence on the thermopower, which, combined with extremely low thermal conductivity values, results in a maximum ZT value of 0.7 at 423 K for x = 0.017 perpendicular to the pressing direction.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 83
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-06-09
    Description: Pulsed laser deposited thin Y Ba 2 Cu 3 O 7−x (YBCO) films with pinning additions of 5 at. % Ba 2 Y TaO 6 (BYTO) were compared to films with 2.5 at. % Ba 2 Y TaO 6 + 2.5 at. % Ba 2 Y NbO 6 (BYNTO) additions. Excellent magnetic flux-pinning at 77 K was obtained with remarkably high irreversibility fields greater than 10 T (YBCO-BYTO) and 11 T (YBCO-BYNTO), representing the highest ever achieved values in YBCO films.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 84
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-06-10
    Description: We report on the transport properties of hybrid devices obtained by depositing graphene on a LaAlO 3 /SrTiO 3 oxide junction hosting a 4 nm-deep 2-dimensional electron system. At low graphene-oxide inter-layer bias, the two electron systems are electrically isolated, despite their small spatial separation. A very efficient reciprocal gating of the two neighboring 2-dimensional systems is shown. A pronounced rectifying behavior is observed for larger bias values and ascribed to the interplay between electrostatic field-effects and tunneling across the LaAlO 3 barrier. The relevance of these results in the context of strongly coupled bilayer systems is discussed.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 85
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-05-26
    Description: We report p-doping of the BaSnO 3 (BSO) by replacing Ba with K. The activation energy of K-dopants is estimated to be about 0.5 eV. We have fabricated pn junctions by using K-doped BSO as a p-type and La-doped BSO as an n-type semiconductor. I-V characteristics of these devices exhibit an ideal rectifying behavior of pn junctions with the ideality factor between 1 and 2, implying high integrity of the BSO materials. Moreover, the junction properties are found to be very stable after repeated high-bias and high-temperature thermal cycling, demonstrating a large potential for optoelectronic functions.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 86
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-05-26
    Description: We present an investigation of the thermoelectric properties of cubic perovskite SrTiO 3 . The results are derived from a combination of calculated transport functions obtained from Boltzmann transport theory in the constant scattering time approximation based on the electronic structure and existing experimental data for La-doped SrTiO 3 . The figure of merit ZT is modeled with respect to carrier concentration and temperature. The model predicts a relatively high ZT at optimized doping and suggests that the ZT value can reach 0.7 at T = 1400 K. Thus ZT can be improved from the current experimental values by carrier concentration optimization.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 87
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-05-27
    Description: With their ability to rapidly elucidate composition-structure-property relationships, high-throughput experimental studies have revolutionized how materials are discovered, optimized, and commercialized. It is now possible to synthesize and characterize high-throughput libraries that systematically address thousands of individual cuts of fabrication parameter space. An unresolved issue remains transforming structural characterization data into phase mappings. This difficulty is related to the complex information present in diffraction and spectroscopic data and its variation with composition and processing. We review the field of automated phase diagram attribution and discuss the impact that emerging computational approaches will have in the generation of phase diagrams and beyond.
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 88
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)
    Publication Date: 2016-05-28
    Electronic ISSN: 2166-532X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 89
    facet.materialart.
    Unknown
    American Institute of Physics (AIP)