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

抄録

  The Curie temperature T_c variation problem in heat-assisted magnetic recording is discussed. We describe the physical implication of the T_c variation problem, and provide ways of improving the writing property by employing our simplified model calculation. The bit error rates for mean Curie temperatures of 600 and 700 K are examined. The T_c variation increases both write-error (WE) and erasure-after-write (EAW). The main related calculation parameters are the grain column number in one bit and the thermal gradient for the down-track direction. Increasing the grain column number is effective in reducing WE and EAW caused by the T_c variation. Furthermore, increasing the thermal gradient is necessary since EAW is high. Although a higher writing field of 12 to 14 kOe is necessary, a bit error rate less than 10^-3 can be achieved for recording densities of 4 or 2 Tbpsi under the conditions used in this study even though the standard deviation of the Curie temperature is 4 %.