Structure and Perpendicular Magnetic Properties of FeBi Films by Evaporation Method

Media for use in perpendicular magnetic recording must have a magnetic anisotropy directed normal to the film surface; as recording densities continue to rise, this method is fast becoming a center of attention. In a previous report, we focused on magnetic thin films with a perpendicular anisotropy caused by the shape anisotropy due to nonmagnetic impurities in films, the orientation of the film crystal and a columnar microstructure, and reported on the magnetic properties of (FeMn)Bi system thin films. In connection with this, we studied the magnetic properties and structure of FeBi thin films, and found that slight changes in the Bi concentration had a profound effect on the growth of crystal grains, with corresponding changes in the magnetization and coercivity of the evaporated ffilms. When columnar grains form in the Fe (110) direction, normal to the substrate, as occurs in 3000 A thick films with a Bi concentration of 1.6 at% and grown at a substrate temperature of approx. 100°C, perpendicular magnetization film with a coercivity of 500 Oe and a remanent magnetization of 630 G is obtained.