3 Gb/in/sup 2/ recording demonstration with dual element heads and thin film disks

Abstract

We have successfully demonstrated magnetic recording at an areal density of 3 Gb/in/sup 2/ with narrow track inductive-write MR-read dual element heads on low noise Co alloy thin film disks. In this demonstration, the write head is a ten turn thin film inductive head with thick and narrow P2 pole-tips. The read head is a shielded /spl sim/1 /spl mu/m trackwidth MR sensor soft-film biased in the read region for linearization and exchange-biased at the tail regions for magnetic stabilization. During recording tests, the heads were flown over low noise Co-alloy media at a clearance similar to that in the previous 1 Gb/in/sup 2/ recording experiment. Results showed good writability from the narrow track write head in terms of overwrite and hard transition shift. Readback yields symmetrical signals as large as 600 /spl mu/V (p-p) and rolloff measurements showed 50% densities as high as 5000 fc/mm. Track profile and microtrack profile measurements showed the write and read trackwidths to be /spl sim/1.4 /spl mu/m and /spl sim/1.1 /spl mu/m respectively, with tight side-writing and side-reading characteristics. An overall assessment of the parametric recording results suggested areal density feasibility up to as high as 3 Gb/in/sup 2/. This projection was confirmed by error rate performance testing using a PRML channel with a digital filter and write precompensation. At a data rate of 4-5 Mb/s and at very low ontrack error, a linear density as high as 185 Kbpi and an optimized track pitch as narrow as 1.5 /spl mu/m were achieved, corresponding to an areal recording density of /spl sim/3.1 Gb/in/sup 2/.