MRヘッド対応高S/N単層垂直磁気記録媒体 (<特集>垂直磁気記録の進展)

概要

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Perpendicular recording media are expected to be used in future hard disk drives with 10-20 Gbits/in^2 areal density. With thicknesses of 50-100 nm, such media have an advantage as regards thermal stability over longitudinal recording media, whose thicknesses are 10-30 nm. The large medium thickness also reduces the demagnetization field and the number of magnetic defects, and increases the signal amplitude. However, the large medium noise is a significant drawback for the perpendicular recording media. We optimized a perpendicular magnetic recording medium for use with a merged MR head designed for longitudinal media. The single-layer Co-Cr perpendicular medium has a similar MR bias current dependence of the signal amplitude and signal distortion to those of a longitudinal medium. The increase in the Cr content from the conventional 22 at% to 28 at% causes an increase in the signal-to-noise ratio of 6 dB. The Ti underlayer helps to increase the recording resolution but not to decrease the medium noise. Cr-rich Co-Cr perpendicular media with large thickness and low M_s value are expected to be used with the future high-sensitivity MR and GMR heads to achieve high-density recording of more than 10 Gbits/inch^2.
社団法人日本磁気学会の論文
1997-06-01