Characterization of Adjacent Track Erasure in Perpendicular Recording by a Stationary Footprint Technique

As the perpendicular recording writer keeps scaling down to improve recording areal density and data rate throughput, the off-track performance of the writer, including both adjacent track erasure and wide area adjacent track erasure, becomes one of the key challenges in hard disk drives. Understanding writer erasure locations and mechanisms is critical. In this paper, stationary footprint technique is used to study various perpendicular writer designs. The asymmetric responses of two side shields in wrapped-around shielded writer are observed, which agree well with micromagnetic modeling results. The impacts of asymmetric side shields on cross track gradient and adjacent track erasure were qualitatively verified. The hot spot locations and mechanisms of wide area track erasure have been investigated. The impacts of recording media and recording reader in stationary footprint measurement are also discussed.