New estimation methods of erase band width and track-edge noise in perpendicular magnetic recording

In order to realize higher track density, improving recording resolution and noise at track edge is one of the crucial issues. It has been considered that the erase band (EB), which appears at track-edge, can suppress the cross-talk noise from the adjacent track. On the other hand, the EB consists of a randomly magnetized area that may emanate track-edge noise. In this study, we estimated the accurate EB width by a newly proposed technique and derived analytical formula of the 747 curve with large EB noise. As a result, we found that the peak of track-edge noise was outside the EB and the EB was enough of a noise source at track edge and may be obstructive to the improvement of track density. A bump of 747 curve was produced in the case of little noise of EB. There is a close relationship between the shape of the 747 curve and the EB noise.