Structure and Magnetic Properties of CoNi Thin Films Epitaxially Grown on MgO(100) and SrTiO (100) Substrates

摘要

CoNi epitaxial thin films were prepared on MgO(100) and SrTiO$_{3}$(100) single-crystal substrates by ultra-high vacuum molecular beam epitaxy. Effects of substrate temperature on the structural and magnetic properties of epitaxial films were investigated. On MgO(100) substrate, CoNi epitaxial films consisting of hcp$(11{bar{2}}0)$ and fcc$(100)$ crystals are obtained whereas on SrTiO$_{3}(100)$ substrate, CoNi$(100)$ single-crystal films with fcc structure are formed. CoNi film growth on both substrates seems to follow the Volmer-Weber mode. CoNi $(100)_{rm fcc}$ single-crystal film with smaller strain is obtained on SrTiO$_{3}$ substrate rather than on MgO$(100)$ substrate. The film strain decreases with increasing the substrate temperature. The magnetic hysteresis loops of CoNi epitaxial thin films reflect the magnetocrystalline anisotropies of hcp-CoNi and fcc-CoNi crystals.