Impact of Curie Temperature Variation on Bit Error Rate in Heat-Assisted Magnetic Recording

Abstract

Heat-assisted magnetic recording (HAMR) is a promising candidate as a next generation magnetic recording method that can operate beyond the trilemma limit1). We have already proposed a new HAMR model calculation2)~4). We have also shown in our improved model calculation that the signal-to-noise ratio derived by the conventionally used micromagnetic calculation can be explained using the temperature dependences of the grain magnetization reversal probability and the attempt period, whose inverse is the attempt frequency5). A feature of our model calculation is that it is easy to grasp the physical implication of the HAMR writing process and the calculation time is short. Since HAMR is a writing method in which the medium is heated to reduce coercivity at the time of writing, the coercivity of the medium can be reduced by any amount. However, micromagnetic simulation has shown that a relatively high writing field is necessary6). The actual HAMR system is very complicated, and various problems are intertwined. Therefore, we have separated problems in a simplified model using our model calculation. We have divided the topic of increasing writing field sensitivity into four problems using the bit error rate calculated with our model for HAMR, and we have discussed the calculation parameters related to the problems7). The four problems are write-error, erasure-after-write6), a statistical problem7), and the damping constant3). It has been reported that variation in the Curie temperature