New CoPt/Ag films for high density recording media

CoPt/Ag nanocomposite films have been prepared with magnetic properties pro mising 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. An nealing leads to a microstructure consisting of the magnetically hard face centered tetragonal CoPt nanoparticles embedded in a Ag matrix. Microstruct ure and coercivity can be tailored by adjusting the annealing conditions an d 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 o btained. Henkel plots of optimally annealed samples show only weak interact ions of dipolar nature, characteristic of magnetically isolated single doma in particles. (C) 1999 American Institute of Physics. [S0021-8979(99)50308- 3].