Structure, hyperfine interactions, and magnetic behavior of amorphous and nanocrystalline Fe80M7B12Cu1 (M=Mo,Nb,Ti) alloys

Fe-57 Mossbauer spectrometry is used to elucidate the structural arrangemen t and nature of hyperfine interactions in amorphous and nanocrystalline for ms of Fe80M7B12Cu1 (M = Mo, Nb, and Ti) alloys. Paramagnetic at room temper ature as-quenched M = Mo amorphous alloy shows a distribution of quadrupole splitting (T-C = 265 K). After partial crystallization, a wide range of hy perfine interactions is observed in the residual amorphous matrix of all sa mples. The hyperfine field distributions corresponding to the amorphous pha se and interfacial zone provide a quantitative basis for a design of topogr aphy of hyperfine interactions. Closer inspection of magnetic interactions is made by the help of unconventional radio frequency (rf) Mossbauer techni que. The rf Mossbauer results show that the nanocrystalline Fe phase has a larger anisotropy than that of the parent amorphous phase. Conventional mag netic measurements, differential scanning calorimetry, x-ray diffraction, t ransmission electron microscopy, and scanning tunneling microscopy experime nts are employed to provide complementary information. (C) 1999 American In stitute of Physics. [S0021-8979(99)03002-9].