High density magnetic recording on highly oriented CoCr-alloy perpendicular rigid disk media

Abstract

Hbs tree t-High density magnetic recording is investigated for a combination of single-layered perpendicular media and ring-type heads. Medium magnetic properties (Hc and Mr/Ms) are improved by introducing a dual underlayer structure. Readwrite experiments show that the linear recording resolution (D5J increases drastically with decreasing the magnetic spacing. D,, values of 190 -220 kFCI are observed using a flying MR head at an estimated magnetic spacing of 40 nm. Using contact recording, even higher resolution of D50*=300 kFCI is confirmed. Side-writing and side-erasing can be reduced below 0.2 pn by employing a narrow gap write head with trimmed sharp track edge, which shows a possibility of track density greater than 25 kTPI. The recording areal density, thus, can he increased to 10 Gbhn' level with the present recording system.

Magnetic microstructures in Co-Cr sputtered thin films for perpendicular recording

“…Track density can be 2S kTPI. It is concluded [14] that taking into account medium noise and overwrite characteristics, signal processing, and bit stability, this single layered/ring head system indicates a possibility of 10 Gbitlin 2 • This density is also claimed by [IS] using a MIG ring head in combination with a double layered medium ( hard Co-Cr layer with a soft magnetic back layer). High output and high linear density recording of over 300 kFRPI was obtained by using Co-Cr-(Nb, Ta, Pt) media in combination with a Single Pole Tip (SPT) head with pole thickness of 0.2 ~ [16].…”

“…The SNR ofPMR with weak exchange interaction are much higher than those of LMR, despite the larger grainsize of the PMR media Also in the case of PMR the Hc is not a very important parameter for high densities because there is no strong relation between this parameter and the linear density as there is in the case ofLMR. In [14], read/write experiments are given from the combination single-layered perpendicular media (Co-Cr-Pt; Co-Cr-Pt-Ta) and ringtype heads. In the case of contact recording using a narrow gap head (gap length < 0.2 ~m) DSO (the linear recording resolution) 300 kFCI is confirmed (implying a bit length of 63 nm).…”

Investigation of High Density Magnetic Recording with Single-layer Perpendicular Media

“…12 indicate that the recording resolution is limited by the shield gap length of MR head. A higher Dso value is expected by using an MR head with a narrower shield gap length [4]. To investigate the potential in increasing the linear recording density characteristics, a 50 nm thick CoCr 17 Ta 4 single layer perpendicular recording medium was recorded using a ring-type head at a contact recording condition.…”

“…This is advantageous to fabricate the high density recording media which require a high level technology to control several parameters simultaneously like crystalline orientation, grain size distribution, decoupling of magnetic exchange, corrosion resistance, etc. The alloying elements control [12.29-34] and the high revel epitaxial thin film growth technologies [4,32] will become more and more important to develop single-layer perpendicular media for high density magnetic recording.…”

“…When this trend is maintained, several problems such as the thermal instability of recorded information and the recording head writability will become serious in the near future. Employment of perpendicular magnetic recording is an effective way to continuously increase the hard disk drive areal density while reducing these physical problems associated with longitudinal recording [3,4]' This situation is illustrated in Fig.l [5]. It is possible to use a thicker recording layer with moderate coercivity in perpendicular magnetic recording.…”