Magnetic properties and microstructural studies of FePt and Fe/sub 50/Pt/sub 50-x/Nb/sub x/ with very high energy product

Summary form only given The FePt and Fe/sub 50/Pt/sub 50-x/Nb/sub x/ thin films were deposited on natural-oxidized Si [100] substrate by rf magnetron sputtering. The concentration of Nb in FePt was 0.00, 0.83, 1.31 and 2.05 atomic percent, respectively. X-ray diffraction data show several Ll/sub 0/ order peaks in the thin films in-situ annealed at 500/spl deg/C for 10 minutes. The intensity of the superlattice peaks decreased as the Nb concentration is increased. It reveals that Nb element reduced the volume percents of the order phase. Another advantages of Nb addition are the increase in remanence (M/sub r/) from 800 emu/cm/sup 3/ (Nb-free) to 1500 emu/cm/sup 3/ (Nb=2.05 at%) due to the increase of high-magnetization alpha Fe and disorder FePt phases. The (BH)/sub max/ value thus was significantly improved from 15.3 MGOe for Nb-free sample to a very high value of 30.6 MGOe for Nb=0.83 at%, accompanied by a decrease of H/sub c/ from 9.5 kOe to 2.0 kOe.