Electrocaloric effects of bulk and thin film Ba(Zr0.08Ti0.92)O3 single crystals

Abstract

The phenomenological Landau-Devonshire theory is applied to investigate the electrocaloric effects of bulk and thin film Ba(Zr0.08Ti0.92)O3 single crystals. The electrocaloric coefficient of 1.36 × 10−3 C/m2K and adiabatic temperature change of 1.0 °C are obtained in tetragonal T phase for bulk Ba(Zr0.08Ti0.92)O3 single crystal with the electric field of 50 kV/cm and field change of 200 kV/cm, respectively. Ba(Zr0.08Ti0.92)O3 thin film with tensile misfit strain has the larger electrocaloric effect in monoclinic M2 phase than that of tetragonal T phase which exists in compressive misfit strain. The compressive misfit strain does not change the maximum of electrocaloric coefficient, but enlarges the maximum of adiabatic temperature change. However, the tensile misfit strain improves the maxima of electrocaloric coefficient and adiabatic temperature change. In addition, the effects of electric field and temperature on electrocaloric effect are studied in tetragonal T phase and monoclinic M2 phase with different compressive and tensile misfit strains respectively. The large electrocaloric coefficient and adiabatic temperature change at the misfit strain of 0.4% are 7.4 × 10−3 C/m2K and 20 °C for Ba(Zr0.08Ti0.92)O3 thin film with the electric field of 50 kV/cm and the field change of 200 kV/cm, respectively. The giant electrocaloric effect in Ba(Zr0.08Ti0.92)O3 thin film may provide the potential for practical cooling device applications.