Direct Measurement of Large Electrocaloric Effect in Ba(Zr_<i>x</i>Ti_1–<i>x</i>)O₃ Ceramics

Abstract

Barium zirconate titanate (BZT) (Ba(Zr_xTi_1-x)O₃) ceramics with Zr⁴⁺ contents of x = 5, 10, 15, 20, 25, and 30 mol % were prepared using a solid-state reaction approach. The microstructures, morphologies, and electric properties were characterized using X-ray diffraction, scanning electron microscopy, and impedance analysis methods, respectively. The dielectric analyses indicate that the BZT bulk ceramics show characteristics of phase transition from a normal ferroelectric to a relaxor ferroelectric with the increasing Zr⁴⁺ ionic content. The electrocaloric effect adiabatic temperature change decreases with the increasing Zr⁴⁺ content. The highest adiabatic temperature change obtained is 2.4 K for BZT ceramics with a 5 mol % of Zr⁴⁺ ionic content.