Coexistence of multiple positive and negative electrocaloric responses in (Pb, La)(Zr, Sn, Ti)O3 single crystal

The electrocaloric effect has been investigated in antiferroelectric (Pb, La)(Zr, Sn, Ti)O-3 (PLZST) single crystals grown by the flux method. The measurements of polarization versus electric field loops on unpoled crystals revealed that at room temperature, a critical electric field of 1.8 kV/mm is needed to induce a ferroelectric phase from an antiferroelectric phase. The dielectric properties demonstrated that the induced ferroelectric phase recovers to antiferroelectric phase when temperature is above the depolarization temperature (70 degrees C-100 degrees C). Coexistence of the negative and positive electrocaloric effect has been achieved in < 001 >-oriented PLZST single crystals. Multiple electrocaloric response values of -0.054 degrees C at room temperature, 0.17 degrees C near the depolarization temperature, -0.14 degrees C at 125 degrees C, and 0.75 degrees C around Curie temperature have been observed under an electric field of 3 kV/mm. The coexistence of multiple negative and positive electrocaloric effects in one material provides a possibility to design solid-state refrigerator technologies to enhance the electrocaloric efficiency. (C) 2016 AIP Publishing LLC.