Epitaxial growth of (Ba, Sr) TiO3 thin films and their ferroelectric properties

Abstract

A series of studies on heteroepitaxial BaxSr1-xTiO3 (BST) films grown by radio-frequency magnetron sputtering was reviewed. It is theoretically suggested that the application of two-dimensional compressive stresses to a ferroelectric crystal raise the Curie temperature. Artificial modification of the Curie temperature was experimentally made by introducing lattice misfit strains in heteroepitaxial films. A heteroepitaxial BaTiO3 film with a thickness of 12 nm grown on a SrRuO3/SrTiO3 substrate exhibited a ferroelectric hysteresis loop at 200°C, even though the inherent Curie temperature is 130°C. The possibility for ferroelectric nonvolatile memory applications of heteroepitaxial BST films and their advantages over Pb (Zr, Ti)O3 or SrBi2 Ta2O9 was discussed.