Ferroelectric properties in epitaxially grown BaxSr1−xTiO3 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 DE 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.