Solid-phase synthesis of Co7Sm2(110) epitaxial nanofilms: Structural and magnetic properties

The solid-phase synthesis of the Co₇Sm₂ and Co₁₇Sm₂ magnetically hard phases in Co/Sm/Co(110) epitaxial film systems has been experimentally investigated. The Co₇Sm₂ phase is first formed at the Sm/Co interface at a relatively low (~300°C) temperature. As the annealing temperature increases to ~450°C, the Co₁₇Sm₂(110) phase grows epitaxially on the Co₇Sm₂(110) phase. The saturation magnetization and biaxial anisotropy constant in the samples vary with the formation of the Co₇Sm₂ and Co₁₇Sm₂ phases. Investigations of the solid-phase synthesis in the nanofilms reveal the existence of a new structure phase transition at 300°C in the Co-Sm system with a high cobalt content.