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Title: NMR and Moessbauer studies of the amorphous system Fe/sub 79/P/sub 21-x/B/sub x/

Technical Report ·
DOI:https://doi.org/10.2172/7099164· OSTI ID:7099164

Combined NMR, spin-echo and Moessbauer experiments have been performed to obtain hyperfine field distributions of the transition metal and metalloid elements in splat-cooled amorphous Fe/sub 79/P/sub 21//sub -x/B/sub x/ alloys. These distributions are related to the local environments of the elements. The NMR signals are observed in the low frequency range 20-60 MHz and all the nuclei, i.e. Fe, P and B, may contribute to the spectral distribution. The resolution of the spectra into that due to Fe and (P + B) nuclei was made possible by using samples prepared with an Fe/sup 56/ isotope. The Fe distribution thus obtaned shows general agreement with the Moessbauer field distribution. From a careful analysis of the NMR data, the hyperfine field at the B nuclei in these amorphous alloys is found to range from 24 to 26 KG increasing with B content. An upper limit of 8 KG for the half-width is attributed to this distribution. The Moessbauer spectra of the Fe/sup 57/ nuclei resemble those for the crystalline Fe/sub 75/P/sub 25//sub -x/B/sub x/ alloys. A fit of the spectra shows a field distribution which suggests the presence of structure. Such a structure may correspond to various Fe sites, also seen in the crystalline alloys. The distributions generally lie between about 160 and 330 KG, with a maximum at about 260 KG. These spectra do not show the presence of Fe nuclei with essentially zero hyperfine field as was obtained for amorphous Fe-Pd-P by Sharon et al. and for amorphous Fe-P by Logan et al. With increasing B content the center of gravity of the Fe distribution shifts to higher values. From a systematic study of the NMR lines and other considerations it is concluded that the P field distribution is broad and its hyperfine field is between 20 and 35 KG for the higher P concentration alloys.

Research Organization:
California Inst. of Tech., Pasadena (USA). W.M. Keck Lab. of Engineering Materials
DOE Contract Number:
EY-76-C-03-0822
OSTI ID:
7099164
Report Number(s):
CALT-822-95; TRN: 77-015217
Country of Publication:
United States
Language:
English