Upper limit of the electrocaloric peak in lead-free ferroelectric relaxor ceramics
American Institute of Physics (AIP)
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.
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics