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Two kinds of perpendicular oxide media are compared with a conventional, boron-alloy media. Using an integrated, 245 nm wide, single-pole, high-Bsat writer with trapezoidal write pole, a linear density of 760 kfci at a BER of 10−5 was achieved at the ID radius of an oxide disk at 5400 RPM. MFM images of written tracks show higher-quality transitions up to a higher linear density on the oxide media. Furthermore, transitions on the B-alloy media exhibit a high degree of curvature. Finally, room temperature measurements of thermal decay on an improved oxide media, with only slightly degraded recording performance, showed the oxide media to be thermally stable.

In addition to achieving high areal density, recording with perpendicular media must be compatible with other elements of disk drive recording. These include use of rotary actuation, the need for offtrack capability, stray field immunity, and servo control of the head position. Rotary actuation implies writing and reading with the head skewed at substantial angles relative to the track, while servo requires clean track edges. A soft magnetic underlayer, while improving the perpendicular write efficiency, exacerbates problems with head skew and stray fields. We have performed experiments related to drive integration, at the component level and by building drives incorporating perpendicular media. We report on the effect of head skew on the drive, particularly for servo and data recovery. We report on a beveled probe head design which minimizes the effect of skew on the servo pattern and track squeeze. In a 20 Gbit/in 2 drive, perpendicular media yields comparable servo and nearly equal areal density performance to longitudinal recording.

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