Signal and noise characteristics of thin film media estimated by magnetic force microscopy

An analytical magnetic force microscopy has been applied to investigate the relationship between the media S/N and the microscopic magnetization irregularities of CoCr-alloy longitudinal and single-layer perpendicular media recorded at linear densities up to 450 kFCL. When the S/N is compared between longitudinal and perpendicular media, a 16-nm-thick CoCrPt longitudinal medium shows a little higher S/N than that of a heat-treated 25-nm-thick CoCrTa perpendicular medium. The medium S/N is found to deteriorate with increasing the size and the number of magnetization transition irregularity.