CoPt : B granular thin films for high density magnetic recording media

Granular CoPt: B films, consisting of high anisotropy, face centered tetrag onal (FCT) CoPt particles embedded in a B matrix have been successfully pre pared. Their structural and magnetic properties are investigated as a funct ion of annealing temperature and boron content, to examine their suitabilit y for magnetic recording media. Grain size and isolation can be adjusted by the boron concentration and annealing process: boron is found to lower the required processing temperature. A minimum grain size is obtained for the 20 vol% B samples for all annealing temperatures. The activation volume as estimated by magnetic relaxation and remanence measurements approaches the physical particle size only for the nanocomposites with grain sizes below 2 0 nm, indicating a coherent rotation mechanism in these dims. (C) 2001 Else vier Science B.V. All rights reserved.