In this study, K(Ta0.60Nb0.40)O3 (KTN) thin films were prepared by the spin-coating method on Pt(111)/Ti/SiO2/Si substrates and varying sintering temperature. KTN coating solutions were synthesized by sol-gel method using metal alkoxide materials. As a result of DTA analysis, an exothermic peak for the crystallization reaction was observed in the temperature range of from 700 oC to 750 oC. KTN thin films sintered at 700-750 oC showed the typical XRD patterns of a polycrystalline perovskite structure. The thickness of the KTN was approximately 203 nm. The dielectric constant and dielectric loss at 1 kHz of the KTN films sintered at 750 oC were 200, 0.08, respectively. Remnant polarization decreased with increasing the temperature, and the value of thin film sintered at 750 oC was 0.18 μC/cm2 at room temperature. The maximum electrocaloric temperature change ΔT of the thin film sintered at 750 oC was about 1.04 oC under a field of 400 kV/cm at 25 oC.

Keywords: Electrocaloric effect, KTN, Ferroelectricity, Hysteresis loop, Sol-gel method.