Ferroelectric properties in epitaxially grown Ba<i>x</i>Sr1−<i>x</i>TiO3 thin films

Abstract

Induced ferroelectricity was observed in epitaxially grown BaxSr1−xTiO3 (BST) thin films with thicknesses of about 220 nm. The BST films with various Ba content were deposited at 600 °C on Pt/MgO substrates, by radio frequency magnetron sputtering with double targets, BaTiO3 and SrTiO3. The epitaxial growth of the BST films was confirmed with x-ray-diffraction and reflection high-energy electron-diffraction analyses. The D–E hysteresis curve and the Curie temperature shift confirmed the BST films with Ba content x≥0.44 had ferroelectricity at room temperature. The mechanism of the ferroelectricity appearance was discussed in relation to the elongation of the c axis in the thickness direction, caused by lattice mismatch between Pt and BST.