High signal-to-noise ratio of a Cr-rich CoCrPt perpendicular medium with a large medium thickness

A Cr-rich (Co₇₂Cr₂₈)₉₄Pt₆ perpendicular medium with a large thickness of 300 nm, integrated with an MR head designed for longitudinal recording, achieved a high signal-to-noise ratio of 37 dB at 100 kFCI and a D₅₀ of 150 kFCI. A high Pt content of 17-22 at.% is effective for increasing the Hk value and signal amplitude at 10 kFCI, and for decreasing the write demagnetization. However, it also decreases the S/N at 100 kFCI and the D₅₀. The signal amplitude rapidly increases with the Pt content from 0 to 6 at.%, and saturates at around 6 at.%. This contributes to the high S/N obtained at a Pt content of 6-11 at.%. Compared with a longitudinal medium optimized for the same MR head, the proposed medium has a 2 dB higher S/N at 100 kFCI, a 1.3 times larger D ₅₀, and a 1.5 times larger signal amplitude at 10 kFCI. The thickness of the medium will contribute to the thermal stability of magnetic bits at future high recording density of 10 Gbits/in² and beyond