Grain growth in ultrathin films of CoPt and FePt

The microstructure of sputtered 10-nm thin films of equiatomic binary alloys of CoPt and FePt was characterized using transmission electron microscopy (TEM). Grain growth kinetics was examined using manual and digital analysis of bright-field TEM images and was seen to take two stages during annealing in these films. A rapid growth stage concurrent with the formation of a [111] fiber texture was observed to occur within the first 5-10 min of annealing, followed by a much slower growth stage after the fiber texturing was well advanced. Differences in grain growth rate and ultimate grain size were also observed to depend on heating rate.