高飽和磁化の薄いソフト層を有するHard/Softスタック垂直媒体の磁気特性と記録再生特性(磁気記録)

概要

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The magnetic properties and recording performance of hard/soft-stacked media consisting of a magnetically hard layer (9-10 nm) underneath a very thin soft layer (2 nm) with a large saturation magnetization were investigated. Magnetic energy calculations revealed that reducing the strength of the interfacial exchange coupling between the hard and soft layers reduces the remanence coercivity, H_r. Moreover, an increase in the saturation magnetization of the soft layer <M_s^<soft>> significantly enhances the H_r reduction. It is theoretically predicted that the grain volume of hard (10 nm)/soft (2 nm) stacked media having <M_s^<soft>> of 1000 emu/cm^3 could be reduced to about 1/3 that of conventional media whilst maintaining good recording writability and thermal stability. An experimental study of stacked media revealed that the magnetization reversal mechanism changed systematically as a function of the strength of the interfacial exchange coupling, as predicted theoretically. The H_r reduction on adjusting the interfacial coupling reached 22% of that of media consisting of directly coupled hard/soft grains. It was successfully demonstrated that hard/soft-stacked media having thin soft layers with a large <M_s^<soft>> showed better recording writability without degradation of SN_mR, recording resolution, or thermal stability.
社団法人日本磁気学会の論文
2007-05-01