197Au NMR study of Au impurities in Fe and FCC Co

NMR measurements of 197 Au in Fe and FCC Co alloys with 0.1 at.% Au have been made using powdered specimens in zero external magnetic field at 1.7K. Electric quadrupole splitting has been found in the spectra. The spacing between the quadrupole-split component lines of FeAu alloy, Delta nu Q , has been determined by the steady-state method to be 0.65+or-0.03 MHz, and the resonance frequency of the central peak nu 0 to be 93.25+or-0.01 MHz, yielding a quadrupole coupling of e 2 qQ/h=1.30+or-0.06 MHz and a hyperfine field of H hf =1258.0+or-0.1 kOe. Analysis of the hyperfine structure anomalies between Au isotopes has given a non-contact field, i.e. an orbital hyperfine field, of +161+or-26 kOe at Au nuclei in iron. Because q will be independent of the isotope, the present and previous results of e 2 qQ/h for Au isotopes in iron have given the nuclear moments 198 Q=0.88+or-0.08 b and 199 Q=0.64+or-0.06 b. For CoAu alloy, Delta nu Q =0.75+or-0.2 MHz and nu 0 =58.0+or-0.05 MHz, corresponding to e 2 qQ/h=1.5+or-0.4 MHz and H hf =782.5+or-0.7 kOe, respectively, have been deduced.