Perpendicular recording CoPtCrO composite media with performance enhancement capping layer

A systematic investigation of the structural and recording characteristics of CoPtCrO composite media with various Co alloys as well as continuous TbFeCo capping layers has been performed. For the media with a Co-alloy capping layer (M/sub s//spl sim/900 emu/cm/sup 3/), the transition jitter remains unaffected and dc noise is greatly reduced. However, for the media with low M/sub s/ capping layer or continuously exchange coupled TbFeCo capping layer, transition jitter is increased. Magnetically continuous but structurally discontinuous Co-alloy capping layers grown onto well-isolated Co grains can reduce dc noise, while maintaining low transition noise.

I. Introduction

Perpendicular recording has been demonstrated to achieve areal density beyond 100 Gb/in² for the next-generation products. Oxygen-doped magnetic alloys such as CoPtCrO have been reported to have small grains with good magnetic decoupling and thermal stability for perpendicular recording media [1], [2]. However, fabrication of well-isolated Co grains with high anisotropy in CoPtCrO media is still a challenge because grain size as well as grain boundary segregation is highly dependent on oxidation that often incorporates into the Co grain, resulting in reduced anisotropy [1]. Moreover, variations in grain boundary segregation in CoPtCrO media will result in a distribution of exchange fields and magnetic cluster size, which increases transition jitter.