Magnetic properties of nonequilibrium bcc and fcc Fe-Pd alloys produced by vapor quenching

Abstract

Fe 1-] x Pd x alloy films obtained by an rf sputtering technique have been investigated by X-ray diffraction, magnetization and Mössbauer effect measurement. All of these alloys are crystalline: a bcc phase for 0< x<0.23, an fcc phase for 0.28< x<1.0 and a bcc-fcc mixed phase for 0.23 < x<0.28. The lattice constant of sputter-deposited Fe 1 x Pd x alloys increases with increasing x, and in the fcc phase the lattice constants are slightly larger than those of the bulk alloys. The Fe 1- x Pd x alloys are ferromagnetic at low temperatures. In the bcc alloys, the hyperfine field and magnetic moment of Fe atoms increase with increasing x. In the fcc alloys, the Mössbauer spectra show a broad ferromagnetic sextet and the hyperfine field decrease, while the magnetic moment of Fe atoms is almost independent of x. The increase in the magnetic moment of Fe atoms is probably due to the volume expansion of Fe atoms by the substitution of Pd atoms with a larger atomic size. The coercive force, H c, in the bcc-fcc mixed phase region is smaller than that in the single bcc and fcc phase regions in sputter-deposited Fe 1- x Pd x alloys.