Preparation and Field-Induced Electrical Properties of Perovskite Relaxor Ferroelectrics

(111)-oriented and random oriented Pb0.8Ba0.2ZrO3 (PBZ) perovskite relaxor ferroelectric thin films were fabricatedon Pt(111)/TiOx/SiO2/Si substrate by sol-gel method. Nano-scaled antiferroelectric and ferroelectric two-phasecoexisted in both (111)-oriented and random oriented PBZ thin film. High dielectric tunability (η = 75%, E = 560 kV/cm) and figure-of-merit (FOM ~ 236) at room temperature was obtained in (111)-oriented thin film. Meanwhile,giant electrocaloric effect (ECE) (ΔT = 45.3 K and ΔS = 46.9 JK-1kg-1 at 598 kVcm-1) at room temperature (290 K), ratherthan at its Curie temperature (408 K), was observed in random oriented Pb0.8Ba0.2ZrO3 (PBZ) thin film, which makesit a promising material for the application to cooling systems near room temperature. The giant ECE as well as highdielectric tunability are attributed to the coexistence of AFE and FE phases and field-induced nano-scaled AFE to FEphase transition.