Hyperfine field distributions in ferromagnetic amorphous FexB1−x thin films

Abstract

Sputtered films of amorphous Fe_xB_1−x (0.40?x?0.50) were studied by Mössbauer spectroscopy. The films were characterized for composition and homogeneity by secondary‐ion mass spectrometry (SIMS) and for lack of crystallinity by X‐ray diffraction. Below the magnetic ordering temperature T_c, the hyperfine spectra consist of a large amplitude quadrupole doublet superimposed on a broad magnetic hyperfine field distribution. The spectra of these alloys are remarkably different from that of polycrystalline FeB and from those of liquid‐quenched alloys which are restricted to compositions near the eutectic at x≊0.8. Comparison with the polycrystalline FeB spectrum clearly shows that for a significant fraction of the Fe atoms in the amorphous alloys, the local environment is substantially different from the Fe environment in FeB.