Perpendicular magnetic recording technology at 230 Gbit/in 2

Abstract

A perpendicular recording system that allows areal densities beyond 200 Gbit/in 2 has been designed and tested to investigate the major challenges in perpendicular magnetic recording. The integrated write/read head has a trailing shield to improve the write head field gradient and a conventional CIP–GMR reader. The medium is a low-noise CoPtCr-based oxide medium with a CoTaZr soft underlayer. On track byte error rates at ∼ 50 Mb/s are better than 10 −4 at ∼1000 kbpi. Using a 15% off-track criterion at 10 −2 byte error rate, track densities between 200–240 ktpi are realized, yielding areal densities of 210–233 Gbit/in 2. High-resolution magnetic force microscopy (hrMFM) has been employed to investigate the write characteristics of these heads with improved cross-track resolution. Using a quantitative analysis method, many parameters, such as transition curvature and transition width, are estimated from the hrMFM image. Significant transition curvature is found, which increases the width of the read head response to a transition, T 50, by 2–3 nm.These results give insights into the recording physics of perpendicular recording and in particular point out improvements required for achieving even higher areal densities.