A study of dilute alloys of iron in gold using the M$ouml$ssbauer effect

Abstract

A detailed analysis of Mössbauer absorption spectra of 57Fe in Au-Fe alloys has been carried through for the concentration range 0·5-12·8% at room temperature and for the 12·8% alloy from room temperature down to 0·4 °K. The results show that significantly different spectra are obtained for iron atoms with 0, 1, 2,... iron nearest neighbours. The concentration dependence of the mean isomer shift is consistent with the changes in charge density to be expected from the changes in atomic volume. As the temperature is reduced, measurable hyperfine fields appear first at iron sites with the largest number of iron nearest neighbours. The quadrupole splitting averaged over all iron sites tends to zero as the temperature is reduced, indicating that the angle between the spin direction and the electric field gradient has a mean value close to cos -1(1/radical3).