Abstract: The regular data are prewritten on the aluminum-based disks by the magnetic encoder system to obtain the sample disks. Taking the sample disks and pico sliders as the investigating objects, the scratch experiments under high-speed sliding contact are performed by Olympus CETR head-disk interface reliability test system. The disk topography and demagnetization are observed by atomic force microscope(AFM) and magnetic force microscope(MFM), and the disk demagnetization phenomena and related statistical researches are analyzed. The results show that the remarkable demagnetization phenomenon can be seen in the serious wear region, which results from the mechanical scratches. The demagnetization phenomenon in the wide but shallow scratch region is mainly caused by the plastic deformation. In some regions, there is only a slight scratch or no obvious scratch on the carbon overcoat in the hard disk. And the corresponding demagnetization area can also be found. The demagnetization phenomenon is mainly attributed to the heat generating from the sliding friction under high-speed sliding contact between the slider and the hard disk and the conductive heat in the layers. The statistic results show that in the absence of severe mechanical damage, the disk demagnetization status has no specific functional relationship with the depth and width of scratches, indicating the heat plays an important role in demagnetization.

Key words: Contact, Demagnetization, Head/disk interface, High-speed sliding