A Study of SNR and BER in Heat-Assisted Magnetic Recording

Heat-assisted magnetic recording (HAMR) is a promising approach to increase the areal density of hard disk drives. The purpose of this paper is to provide a computational framework for optimizing the HAMR system. In order to do that, an integrated HAMR simulation system was built. We then studied several factors that could affect the playback signal-to-noise ratio (SNR), such as the switching time of the writing field, the peak temperature of the heat spot, the standard deviation of anisotropy field and exchange parameters, and the size of the reader element. We found that bit length (BL) becomes the key factor for the value of SNR for small, e.g., 10 nm, BLs. We established a relationship between the SNR and the bit error rate so that it will be easy to predict the storage capacity based on the playback SNR. This curve is used to predict the possible storage capacity for different BLs.