Surface growth dependence in growth of half-metallic Sr2FeMoO6 epitaxial films fabricated by ultra-high vacuum sputtering

Sr2FeMoO6, a double-perovskite half-metallic ferromagnet, has attracted much attention because of its high Tc of 420 K. However, simultaneously balancing the stoichiometry and ordering of a quaternary oxide is no trivial matter. Despite nearly a decade of research, the growth of a half-metallic thin film remains an open question. We have deposited pure-phase Sr2FeMoO6 epitaxial films on SrTiO3 substrates by ultrahigh vacuum off-axis magnetron sputtering, and found double perovskite ordering in excess of 90{\%}. We will discuss the effect of stoichiometry, oxygen content, growth pressure, and ordering in the initial stages of growth on the properties of the sample, by performing a variety of characterizations (HAADF TEM, XRD, XPS, RBS) on both 2-5 unit cell and 100 nm thick films.