Influence of magnetic cluster size distribution on SNR and bit error rate in perpendicular magnetic recording

The bit error rate (BER) and signal-to-noise ratio (SNR) of perpendicular recording media were investigated with a software channel and magnetic clustering based microstructure model of irregular magnetization transitions. The calculations show that the BER is not only determined by the mean cluster size, but also by the fractional standard deviation, as is the SNR. However, the BER performance does not correlate well with the SNR. Reducing the cluster size distribution is more effective at improving the BER than the SNR. An explanation for this discrepancy can be found by considering the distribution of transition position fluctuations and transition percolation.