Abstract

Dielectric and direct temperature changes induced by an electric field were investigated in a ⟨011⟩-oriented 0.72Pb(Mg₁_/₃Nb₂_/₃)O₃-0.28PbTiO₃ single crystal as a function of temperature. Field-induced temperature changes were measured directly from the surface of the crystal by a thermocouple. Three distinct anomalies at temperatures of ~ 68, ~96, and 128 °C were identified in the dielectric and temperature change responses of the crystal, dividing the temperature range into four distinct phase stability regions with different field-induced behaviors. Just above the depolarization temperature of 128 °C, dielectric hysteresis showed a double-loop nature caused by a reversible nonpolar-polar phase transition accompanied by an increase in the electrocaloric temperature change. Two other reversible field-induced phase transitions with different field-induced thermal behaviors were evidenced in the polarization and temperature responses in the temperature ranges of 96–128 °C and below 68 °C.