Study of Nano-grinding for GMR Magnetic Recording Head

The objective of this research is to better understand in what way the ultra smooth hard disk magnetic head (the individual head also called ´slider´) surface is formed in nanogrinding. A float-piece polisher was used to achieve ultra smooth and planar surface in nano-grinding way. The SEM was used to observe the diamond abrasive used in nano-grinding and the plate embedded with diamond abrasive. The slider surface was measured with SEM and AFM before and after nano-grinding. Though the micro-cutting of the continuous plane of the slider surface may exit, it was demonstrated that the un-continuous asperity of the slider surface can´t be ignored in nano-grinding. According to the statistic analysis of the slider surface, the asperities are removed and replaced by a series of smaller asperities step by step, in this way, smoother surface is achieved gradually, and finally, a sub-nanometer smooth surface was achieved. A theoretical model was developed to illustrate the removal of single asperity removed by abrasive. The removal force taking by a single abrasive was calculated according to the model. Pole tip can be protected in some extent because of the regular arrange of the abrasive, so more planar slider surface was achieved in nano-grinding. Combined with the model and the distribution of the asperity of slider surface, the quality of the slider surface can be estimated and the nano-grinding procedure can be optimized.