Influence of magnetic field and mechanical scratch on the recorded magnetization stability of longitudinal and perpendicular recording media

The influences of magnetic field and mechanical scratch on the magnetization structural stability are investigated for longitudinal (LMR) and perpendicular (PMR) recording media by using a magnetic force microscope. For both media, the magnetization structure started to change at lower magnetic fields in the areas near and below mechanical scratches when compared with normal areas with no scratches. For PMR samples, the magnetization stability of recorded bits near and below mechanical scratches is enhanced with increasing the area density. The recorded magnetization stability decreases near and below mechanical scratches depending delicately on the depth and the width for both types of media.