Temperature dependences of the electromechanical and electrocaloric properties of Ba(Zr, Ti)O3 and (Ba, Sr)TiO3 ceramics

The electrocaloric properties of Ba(Zr, Ti)O-3 and (Ba, Sr)TiO3 ceramics (BZT and BST, respectively) were investigated by the indirect estimation and direct measurement of temperature-electric field (T-E) hysteresis loops. The measured T-E loops had shapes similar to those of the strain-electric field (s-E) loops. The measured temperature changes (Delta Ts) at around 30 degrees C of the BZT ceramics sintered at 1450 degrees C and BST ceramics sintered at 1600 degrees C upon the release of the electric field from 30 kV/cm to 0 were 0.34 and 0.57 K, respectively. The temperature dependences of the electromechanical and electrocaloric properties were investigated. The BZT ceramics sintered at 1450 degrees C exhibited the largest electromechanical and electrocaloric properties at around 30 degrees C, which corresponds to the phase transition temperature. BST is more temperature dependent than BZT. BST ceramics sintered at 1600 degrees C exhibited the largest electromechanical and electrocaloric properties at around 29 degrees C, which is about 10 degrees C higher than the phase transition temperature. (C) 2017 The Japan Society of Applied Physics