Microstructure and ordering parameter studies in multilayer [FePt(x)/Os]{sub n} films

The microstructure, ordering parameter, and magnetic properties of multilayer [FePt(x)/Os]{sub n} films on glass substrate by dc-magnetron sputtering (with x being thickness in nm; Os with a fixed thickness 5 nm; n being the number of layers) have been studied as a function of the annealing temperatures between 300 and 900 deg. C. The grain size of multilayer films can be controlled by annealing temperature and thickness of the FePt layer with Os space layer. The coercivity as a function of the annealing temperature for samples with n = 1 and pure FePt behaves roughly saturated after annealing above 700 deg. C. However, for samples with n > 4 the value of H{sub c} seems still increasing with increasing annealing temperature between 600 and 900 deg. C, and the ordering parameter decreases with increasing the number of Os layers. Our experimental results are reasonably well to describe the effect of strain-assisted transformation.