Electric-field-induced dielectric and temperature changes in a ⟨011⟩-oriented Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystal

Dielectric and direct temperature changes induced by an electric field were investigated in a < 011 >-oriented 0.72Pb(Mg1/3Nb2/3)O-3-0.28PbTiO(3) 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 similar to 68, similar to 96, and similar to 128 degrees 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 degrees 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 degrees C and below 68 degrees C.