Interface engineering in epitaxial growth of layered oxides via a conducting layer insertion

Abstract

There is a long-standing challenge in the fabrication of layered oxide epitaxial films due to their thermodynamic phase-instability and the large stacking layer number. Recently, the demand for high-quality thin films is strongly pushed by their promising room-temperature multiferroic properties. Here, we find that by inserting a conducting and lattice matched LaNiO3 buffer layer, high quality m = 5 Bi6FeCoTi3O18 epitaxial films can be fabricated using the laser molecular beam epitaxy, in which the atomic-scale sharp interface between the film and the metallic buffer layer explains the enhanced quality. The magnetic and ferroelectric properties of the high quality Bi6FeCoTi3O18 films are studied. This study demonstrates that insertion of the conducting layer is a powerful method in achieving high quality layered oxide thin films, which opens the door to further understand the underline physics and to develop new devices.