Demonstration of 35 Gbits/in(2) in media on glass substrates

A recording density of 35 Gbits/in(2) was achieved in longitudinal recordin g media with high-sensitivity GMR heads. The media displayed excellent ther mal stability as a result of a CoPtCrB alloy with high magnetocrystalline a nisotropy and relatively narrow grain size distribution. The degree of Co e asy-axis orientation in the plane of the film was greatly improved and the grain size was reduced in the media on glass substrates, Estimates of the s witching volume from dynamic coercivity and signal-to-noise measurements ar e larger than the physical grain size, suggesting that intergranular intera ctions improve stability. A potential path to further increases in recordin g density above 35 Gbits/in(2) is to use antiferromagnetically coupled magn etic layers in the media.