Coercivity Mechanism in Data Storage Media

Abstract

-The coercivity mechanism in polycrystalline CoCrPt thin films, ColPt multilayer systems and in amorphous TbFeCo thin films was studied by analyzing the field and time dependencies of the magnetization. The initial susceptibility Xo and the apparent coercivity as deduced from measuring minor loops indicate a much larger contribution of reversible magnetization processes and a much broader switching field distribution in the polycrystalline CoCrPt magnetic recording medium as compared to the perpendicular magneto-optic ColPt and TbFeCo media. The magnetic interactions in the media have been determined by oM measurements yielding the strongest interactions in the amorphous TbFeCo films and the smallest in the polycrystalline CoCrPt films. Analyzing the relaxation behavior of the magnetization the Barkhausen volume was estimated for all the three media and compared with the results from microstructure analysis by TEM and AFM.