Mössbauer investigation of sputtered ferromagnetic amorphous FexB100−x films

Abstract

Iron boride amorphous films were prepared by rf sputtering of polycrystalline FeB and Fe2B powders. The films were analyzed for purity, uniformity, and composition by secondary ion mass spectrometry and were analyzed for lack of long range order by x-ray diffraction. As in the melt quenched alloys, Mössbauer spectra revealed a broad and nearly symmetric distribution of hyperfine fields in samples with a composition near a-Fe2B. The hyperfine field distribution in samples with a composition near a-FeB, however, is asymmetric, and more significantly, reveals a large number of Fe sites with zero magnetic hyperfine field at temperatures down to 10 K. Analysis of the data throws light on the chemical short range order in the alloys.