Side fringing of thin film heads with pole trimming

A technique for measuring write and erase widths using a narrow-track MR (magnetoresistive) probe to acquire the dual-track profiles of write/overwrite tracks has been developed. This technique was used to reveal the distinct features of shoulder effects on the side-writing and side-erasing behavior of pole-tip trimmed heads. Another technique, using the microtrack profile, was utilized to demonstrate the impact of the low shoulder on the side reading of trimmed heads. Trimmed heads which have a shoulder within 5 μm of the air-bearing surface exhibit modified side-fringing characteristics for the heads and disks studied. The trimmed heads with a shoulder height exceeding 6 μm show substantially smaller erase and read widths, and a weaker dependence of write width on transition density when compared with an untrimmed head having unequal pole widths