Current progress of single-pole-type GMR heads for perpendicular recording

We studied several proposals to address the problems encountered when single-pole-type giant magnetoresistive (SPT-GMR) heads are applied to an actual recording system. The first area of problems was regarding side erasure when there is a head skew. We fabricated a trapezoid-shaped main pole using a focus-ion-beam trimming or using a new wafer-processing technique and examined their write performances and their effects on reducing side erasure. The second area of problems concerned the stray field robustness of SPT-GMR heads when combined with a double-layered perpendicular recording medium. We tried to optimize the robustness and write performance by changing the width of a yoke in the main pole or by positioning a shield above the main pole. The stray field robustness and write performance were adequate in both cases, but a tradeoff relationship exists between both performances.