New CoPt/Ag films for high density recording media

CoPt/Ag nanocomposite films have been prepared with magnetic properties promising for potential application in high density magnetic recording media. The films were initially deposited by sputtering, in a multilayer form and found to crystallize in the magnetically soft face centered cubic phase. Annealing leads to a microstructure consisting of the magnetically hard face centered tetragonal CoPt nanoparticles embedded in a Ag matrix. Microstructure and coercivity can be tailored by adjusting the annealing conditions and the relative CoPt/Ag composition. Values of coercivity in the range of 1-17 kOe with grain sizes in the range of 7-100 nm, respectively, have been obtained. Henkel plots of optimally annealed samples show only weak interactions of dipolar nature, characteristic of magnetically isolated single domain particles. (C) 1999 American Institute of Physics. [S0021-8979(99)50308-3].