Structural and magnetic properties of (100)- and (110)-oriented epitaxial CrO2 films

Abstract

We report the successful growth of epitaxial CrO2 (100) and CrO2 (110) films by chemical vapor deposition on TiO2 (100) and TiO2 (110) substrates, respectively. Films on TiO2 (100) follow a layer-by-layer growth mode, with smooth surfaces but significant out-of-plane compressive stress. In contrast, films on TiO2 (110) follow an islandlike growth mode and are found to be essentially strain free for even the thinnest films studied (∼35 nm). The substrate-induced stress for (100) films plays a dominant role in the evolution of the magnetic anisotropy with increasing film thickness, while (110) films show little variation in anisotropy with film thickness. As a result, the in-plane angular dependence of the saturation fields for (110) films can be understood by presuming domain wall nucleation and motion for small angles with respect to the easy axis and by coherent rotation for angles approaching the hard axis.