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-tonoise 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 DSO- 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 D50, 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. ©1997 IEEE.