Energy product enhancement in Fe/sub 49-x/Co/sub x/Pt/sub 51/ thin films

In this paper, energy product (BH)/sub max/ enhancement in Fe/sub 49-x/Co/sub x/Pt/sub 51/ thin films is investigated. The thin films are fabricated by rf magnetron sputtering and later are annealed at temperature range of 400-700/spl deg/C. Crystal structure is identified by X-ray diffraction and results indicate that the ordering transformation is extensively observed as the FePt sample is annealed at 400/spl deg/C. Addition of cobalt is harmful for the formation of the L1/sub 0/ ordered structure because the starting temperature for ordering transformation is increased. H/sub c/ values for FePt and FeCoPt thin films are increased with annealing temperature while the M/sub r/ is decreased. The (BH)/sub max/ of cobalt-containing thin films is found to be much larger than that of the binary samples. The enhanced (BH)/sub max/ of the cobalt alloyed films is mainly obtained by improving the coercive squareness ratio (S*) and M/sub r/. The optimum degree of ordering transformation and smaller particle size are found to contribute in the enhanced magnetic properties of the FeCoPt thin films.