Trailing shield design for reducing wide area track erasure (water) in a perpendicular recording system

Abstract

A magnetic structure for use in a magnetic head for avoiding wide angle track erasure and other forms of adjacent track interference. The magnetic structure includes a trailing shield having a specially configured back edge opposite the air bearing surface ABS. The magnetic shield has a shallow substantially constant throat height at a center portion. Then, the back edge of the shield tapers back away from the ABS in first and second intermediate portion located at either side of the center portion. These intermediate portions lead to first and second outer portions that have substantially constant throat heights that are larger than the throat height at the center region. The throat height at each of the laterally outer portions can be 1.5 to 5 times the throat height of the center portion. This configuration, chokes off stray fields that might be picked up by the outer portions of the shield preventing excessive magnetic flux from reaching the central portion of the shield where it might affect writing. In addition, the limited throat height of the outer portion (ie. the back edge of the outer portions does not keep tapering back away from the ABS) prevents the outer portions from picking up too much stray magnetic field, while also ensuring that sufficient magnetic material will be present to absorb desired magnetic field from the write pole during use.