Large electrocaloric effect in lead-free Ba(ZrxTi1-x)O3 thick film ceramics

Barium zirconate titanate (Ba(Zr x Ti 1-x )O 3 ) thick film ceramics were prepared using a tape-casting method. Their structures, morphologies, and electric properties were characterized using XRD , SEM and impedance analysis approaches, respectively. The electrocaloric effects (ECE), i.e., isothermal entropy changes and adiabatic temperature changes, were calculated using a Maxwell relation. It was confirmed by XRD and SEM that the obtained thick film ceramics are pure and dense perovskite structures. The dielectric analyses indicate that the Ba(Zr x Ti 1-x )O 3 thick film ceramics show characteristics of transition from normal to relaxor ferroelectrics with the increasing Zr 4+ ionic content. The polarization – electric field (P-E) hysteresis loops reveal larger polarizations and the ceramics can withstand an electric field as high as 12 MV/m. The adiabatic temperature changes ΔT calculated via the Maxwell relation and the polarization as a function of temperature, which is extracted from the P-E hysteresis loops measured at 12 MV m −1 are from 3.7 to 0.28 K with the increasing Zr 4+ ionic content.