Data Loss and Demagnetization of Perpendicular Magnetic Recording Disk Under Sliding Contact

Data loss and demagnetization of perpendicular magnetic recording disk under sliding contact were investigated experimentally. The data loss tests of the disk against a diamond tip under normal forces (0.005–0.05 mN) and the scan of the disk with the magnetic head were sequentially carried out. Then, the demagnetization tests under normal forces (6–10 mN) were performed on the disk to examine the demagnetization behavior. After the tests, the sliding contact areas in the disk samples were observed by atomic force microscopy and magnetic force microscopy. The results showed that data loss occurred without any scratch damages on the disk and demagnetization of the magnetic medium did not occur in the data loss area. The demagnetization occurred only when the scratch depth in the disk exceeded the thickness of the diamond-like-carbon top layer. Finally, a method to study the relationship between data loss and demagnetization of the perpendicular magnetic recording disk under sliding contact was proposed and the conclusion was given that data loss of the disk was not induced by demagnetization of the magnetic medium.