Microscopic magnetization structures and noise in single-layer perpendicular thin film media

A new method to evaluate microscopic magnetization intensities has been developed based on a magnetic force microscopy (MFM) observation. The MFM tip-to-sample distance is varied to get quantitative information at the magnetic layer surface. The method is applied to investigate the origin of medium noise in single-layer perpendicular media. The irregular magnetization in the DC erased state and the average size of magnetization irregularities are quantitatively evaluated for CoCr-alloy perpendicular media with different noise characteristics.