Evaporated Fe-Ni Films for a Back Layer of Perpendicular Magnetic Recording Media I: the Origin of High Coercivity

The cause of the high coercive force of permalloy evaporated films was investigated. The change in Hc with temperature was large when compared with change in saturation magnetization with temperature, refuting the hypothesis that shape magnetic anisotropy is the origin of perpendicular magnetic anisotropy. The ultimate origin of the high coercive force in permalloy evaporated films was found to be magnetic elastic anisotropy causing perpendicular anisotropy. The perpendicular anisotropy generates stripe domains which make magnetic inversion very difficult, producing a high coercive force.