Analysis for Magnetized State of Perpendicular Magnetic Recording Media Using MFM

A method using MFM was investigated for analyzing the magnetization state of CoCrPtTa perpendicular magnetic recording media. Adequate resolution to determine the magnetic cluster size was obtained at a sample-tip spacing of less than 50 nm. The magnetic cluster size obtained in MFM analysis corresponded to the experimental value obtained using an MR head. Ratio of white to black area in dc erased state however, seems to have little correlation with squareness obtained from M-H loop. Time dependence of MFM images revealed the occurrence of thermal decay of the magnetic cluster. Hence it is necessary to take the thermal stability of the magnetic cluster into account in analysis for perpendicular magnetic recording media.