Amorphous rare-earth–transition-metal thin films with an artificially layered structure

Abstract

We investigated the origin of magnetic anisotropy in rare-earth–transition-metal (RE-TM) thin films with an artificially layered structure and their magnetic and crystallographic properties. The various RE-TM films such as Gd-Fe, Tb-Fe, and Dy-Fe were deposited in an alternating multilayer structure by a multisource dc-sputtering method. We made films with an anisotropic distribution of RE and TM atoms parallel to the film plane, where the monatomic layering of RE and TM was confirmed by small angle x-ray diffraction analysis. The films were thermally stable to temperature up to 400 °C. The films composed of monatomic layer of RE and several atomic layers of TM show a large perpendicular uniaxial anisotropy and a large magnetization over a wide range of RE composition. It is concluded that the anisotropic distribution of RE-TM pairs is the most important origin of the magnetic anisotropy in amorphous RE-TM films.