Low noise design of perpendicular magnetic recording media

The basic comprehensive design for low noise perpendicular magnetic recording media is studied. High squareness in perpendicular M-H loop and reduced magnetic domain size are the key properties for media with a low noise property. High squareness also favors thermal stability of recorded magnetization. Co-Cr based alloys are expected to be the candidate material for high recording density media far beyond 100 Gbit/in(2) recording in terms of thermal issue while alternative materials with higher anisotropy should be introduced for the media aimed at 1 Tbit/in(2). Reducing the domain size is the present issue for decreasing medium noise in double layered media. Although it is superficially contradictory to the low noise condition, the slope of the M-H loop should be kept steep to obtain a high recording performance. Paradigm shift from simple magnetic decoupling in the design of such media might be required. (C) 2001 Elsevier Science B.V. All rights reserved.