Analysis of Relation Between Magnetic Cluster Size Distribution and Signal Quality for High-Density Recording

We examined the relationship between media cluster size distribution and signal quality to obtain a guideline for developing high-density recording media. Both spin-stand measurement and micromagnetics simulation were used. The cluster size distribution and signal-to-noise ratio (SNR) of various recording media were evaluated, and the relationship between the two was analyzed by multiple regression. The results demonstrate that the media SNR could be quantitatively estimated from the cluster size distribution (both average sizes and size deviations). Although reducing either the average size or the size deviation was effective for improving the SNR, the impact of reducing the average size was much larger. Moreover, the influence of the average size on the SNR increased as linear density increased due to transition percolation. We concluded that providing guidelines for developing each individual medium at the target recording density is a key step. For high-density recording, in particular, focusing on a small average cluster size is essential in developing media.