在高速滑动接触条件下磁层退磁现象的试验研究

Experimental Research on Demagnetization of Magnetic Layer under High-speed Head/Disk Sliding Contact

运用磁编码系统对铝基磁盘预写入一定规律的数据,制得样品磁盘。以样品磁盘和皮米磁头为研究对象,利用OlympusCETR头盘界面可靠性试验系统,在高速滑动接触条件下进行磁盘刮痕试验;借助原子力显微镜(Atomic force microscope,AFM)和磁力显微镜(Magnetic force microscope,MFM)观察试验后磁盘的形貌和退磁状态,并进行数据分析和统计研究。试验结果表明,在磁盘磨损严重的区域可以看到明显的退磁现象,这主要是由于机械划刮引起的。在宽度大深度浅的刮痕区域中的退磁现象主要是由于塑性变形引起的。在有些区域中,磁盘表面的硬碳层上仅有轻微的刮痕或者无明显的刮痕存在,同样也能在相应的区域中观察到退磁现象,这主要是由于磁头与磁盘间高速滑动摩擦所产生的热和磁盘各介质层间的热传导引起的。统计结果表明,在没有严重机械损坏的情况下,磁层的退磁状态与磁盘的刮痕深度和刮痕宽度没有特定的函数关系,此时热在退磁现象中起到重要的作用。

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.