Electro-caloric properties of KTa0.60Nb0.40O3 thin films prepared by sol-gel method

Abstract

In this study, K(Ta0.60Nb0.40)O-3 (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 degrees C to 750 degrees C. KTN thin films sintered at 700-750 degrees C 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 degrees C were 200, 0.08, respectively. Remnant polarization decreased with increasing the temperature, and the value of thin film sintered at 750 degrees C was 0.18 mu C/cm(2) at room temperature. The maximum electrocaloric temperature change AT of the thin film sintered at 750 degrees C was about 1.04 degrees C under a field of 400 kV/cm at 25 degrees C.