High bit density (100 Mb/cm/sup 2/) with single-layer Co-Cr media and ring heads in perpendicular magnetic recording

The signal and noise of single-layer Co/sub 79/Cr/sub 21/ media are measured with ring heads to estimate the area density that can be achieved. Densities as high as 100 Mb/cm/sup 2/ (1 mu m/sup 2//bit) are expected when a signal-to-noise ratio sufficient for an error probability less than 10/sup -5/ is required. As a comparison, densities estimated from data from metal-evaporated tape and CrO/sub 2/ tape are given. In the frequency response of the single-layer media, an additional minimum was observed for a wavelength slightly larger than the gap length. This is probably caused by the bipolar nature of the perpendicular recording field of a ring head.<
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