Effects of exchange interaction and grain size distribution on cluster size in perpendicular media

Computer simulation was used to investigate the effects of exchange interaction between adjacent grains and grain size distribution on cluster size of perpendicular magnetic recording media. The cluster size was determined from the correlation in the remanent magnetization state (Mr=0) in the Mr-H loop. The cluster size increases with increasing exchange interaction, but it decreases with increasing grain size distribution. Exchange interaction between grains can be obtained from cluster size, grain size distribution, saturation magnetization,anisotropy field, average grain size, and temperature