Growth and properties of high-Curie-temperature Sr2CrReO6 thin films

Abstract

Thin films of ordered double-perovskite ${\mathrm{Sr}}_2\mathrm{Cr}\mathrm{Re}{\mathrm{O}}_6$ have been grown epitaxially onto $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_3$ substrates by sputtering, and their microstructural, electrical, and magnetic properties are investigated. It is found that a wide growth-temperature range of at least $700–800°\mathrm{C}$ can yield epitaxial films with superior magnetic properties and atomically flat surfaces. These films exhibit Curie temperatures $T_c$ of up to $620\mathrm{K}$ , and saturation magnetizations $M_s$ of $0.9{\mu }_B∕\text{formula}$ unit (f.u.), which is comparable to the predicted value of $1{\mu }_B∕\mathrm{f.u.}$ for the fully ordered half-metallic material. Owing to the wide temperature window for growth of high-quality films, the surface morphology and coercivity of ${\mathrm{Sr}}_2\mathrm{Cr}\mathrm{Re}{\mathrm{O}}_6$ films are highly controllable, which is favorable for fabrication of magnetic tunnel junctions.