Magnetic properties of FePt and Fe50Pt50−xNbx(x=0.00, 0.83, 1.31, 2.05) thin films

Abstract Large magnetization values were obtained by fabricating a Fe 50 Pt 50− x Nb x thin film containing an ordered γ 1 phase and a disordered γ structure. The improvement in remanence can be attributed to the exchange coupling between hard magnetic γ 1 phase and soft magnetic γ phase as investigated from Δ M plots. Both H c and B r were increased by an optimum addition of 0.8 at% Nb. The best magnetic hysteresis data were achieved from a Fe 50 Pt 49.2 Nb 0.8 film as follows: B r =12.2 kG, H c =4.3 kOe, ( BH ) max =30.6 MGOe. X-ray diffraction data indicated that Nb plays a role as a grain refiner and can enhance the formation of disordered γ phase.