Pinning of written bits in perpendicular recording media

A perpendicular medium comprising two distinct magnetic layers is described. One layer has a granular structure with isolated, exchange-decoupled grains and the other is a continuous, exchange-coupled layer. In the combined structure dain wall movement is restricted and reversed grains within written bits are eliminated. The S/N ratio is improved compared with single layers of either type alone. © 2001 Elsevier Science B.V. All rights reserved.