Continuous/Cluster-Pinned Recording Media

Authors

Ralph Skomski, University of Nebraska at LincolnFollow
M. L. Yan, University of Nebraska-LincolnFollow
Yinfan Xu, University of Nebraska - LincolnFollow
David J. Sellmyer, University of Nebraska-LincolnFollow

Date of this Version

6-2007

Comments

Published in IEEE TRANSACTIONS ON MAGNETICS, VOL. 43, NO. 6, JUNE 2007. Copyright © 2007 IEEE. Used by permission.

Abstract

We propose and theoretically investigate a new class of nanostructured magnetic recording films, cluster-pinned recording media. The films consist of magnetic clusters exchange coupled to a continuous hard layer with perpendicular anisotropy and low coercivity. Our calculations yield the coercivity and the cross-track correlation length as a function of film thickness and pinning density and strength. The mechanism is very similar to the Gaunt–Friedel pinning in bulk magnets, which differs from ordinary strong pinning by the selfconsistent dependence of wall curvature and coercivity on defect concentration. The main difference is the exponent for the coercivity as a function of the pinning strength, which is equal to 2 in the bulk but equal to 3/2 in thin films. The pinning strength is estimated for various regimes, and it is shown that the diminished domain-wall curvature reduces jitter.