High Density Perpendicular Recording With Wrap-Around Shielded Writer

Abstract

Wrap-around shielded writers combining both trailing shield and side shield have been studied both by modeling and by experiments. WAS design is demonstrated to have superior performance over its predecessor trailing shielded writer in perpendicular magnetic recording systems. While maintaining the down-track performance, the side shield significantly reduces the side fringing field, thus enabling high track densities. In this paper, various aspects of WAS design are investigated. Issues unique to side shielded design such as near and far track erasure are also discussed in detail. An outlook of future PMR writer and recording systems design is presented at the end.Index Terms-Adjacent track erasure, far track erasure, perpendicular recording, side shield, wrap-around shield.

Method for Analysis of On-Track and Off-Track Shielded Magnetic Write Head Recording Performance Based on Write Current Waveform Shaping

“…On-track performance is strongly controlled by using write current transitions with an overshoot (OS) defined by steady state current , OS amplitude, switching rise time, and OS duration [1]. On the other hand, off-track performance, degraded by adjacent/side track erasure, is strongly dependent on magnetization evolution in the shields [2]- [4] which is also affected by the write current waveform shaping. Unfortunately, on-track and off-track performance are often inversely correlated; the down-track recording improvement may come at a cost of adjacent track erasure generated by a magnetostatic field below the side shields.…”