Structural and electrical properties of (Ba0.7Sr0.3)TiO3 thin films for the application of electro-caloric devices

Abstract

This study was conducted on the structural and electrical properties of (Ba0.7Sr0.3)TiO3 thin films prepared by the sol-gel and spin-coating methods in order to investigate their applicability to electrocaloric devices. All specimens showed a tetragonal crystal structure and lattice constants of a = 3.972 angstrom, c = 3.970 angstrom. The mean grain size of specimens sintered at 800 degrees C was about 30 nm, and the average thickness of 5 times coated specimens was 304 similar to 311 nm. In the specimen sintered at 750 degrees C, The relative dielectric constant and loss of specimens measured at 20 degrees C were 230 and 0.130, respectively, while dependence of the dielectric constant on unit DC voltage was -8.163 %/V. The remanent polarization and coercive fields were 95.5 mu C/cm(2) and 161.3 kV/cm at 21 degrees C, respectively. And, the highest electrocaloric property of 2.69 degrees C was observed when the electric field of 330 kV/cm was applied.