Microstructure and enhanced in-plane ferroelectricity of Ba[sub 0.7]Sr[sub 0.3]TiO₃ thin films grown on MgAl₂O₄ (001) single-crystal substrate

Abstract

The microstructure and in-plane dielectric and ferroelectric properties of highly oriented Ba[sub 0.7]Sr[sub 0.3]TiO₃(BST) thin film grown on MgAl₂O₄ (001) single-crystal substrate through pulsed laser deposition were investigated. X-ray diffraction measurements indicated that BST had a distorted lattice with a tetragonality a/c=1.012. The cross- sectional observation under transmission electron microscope revealed that, while most of BST grains grew epitaxially on MgAl₂O₄, the film also contained a noticeable amount of misoriented grains and dislocations. The electrical measurements indicated that the film had a shifted Curie temperature (T[sub C]=78 °C) and an enhanced in-plane ferroelectricity (remnant polarization P[sub r]=7.1 µC/cm²) when compared with BST ceramic (T[sub C]≈33°C and P[sub r]≈0).