Magnetization reversal, coercivity, and the process of thermomagnetic recording in thin films of amorphous rare earth-transition metal alloys

A model is proposed for the mechanism of magnetization reversal in thin films of amorphous alloys with perpendicular magnetic anisotropy. Examples of these alloys are TbFe, GdCo, DyFe, and GdTbFeCo, which are currently under investigation as storage media for erasable optical recording applications. The model exhibits the observed behavior of the media such as nucleation and growth of reverse-magnetized domains under external magnetic fields; square hysteresis loops; temperature dependence of coercivity; formation and stability of domains under conditions of thermomagnetic recording; and incomplete erasure with insufficient applied fields.