Off-track response versus shield width at the ABS for MR heads

The shield width of an MR head is an important factor in the off-track performance of the head. The shields reduce the off-track magnetoresistive pickup of the MR element, however, the inductive response of the shields is a source of off-track coherent noise which can be detrimental to disk drive performance. In this study, the off-track magnetoresistive response is modeled for heads with varying shield widths at the ABS. Using Focused-Ion-Beam processing, heads of varying shield widths were fabricated and compared to the model. The minimum shield width was determined to be six gap lengths wider than the MR element.