Influence of isomer-shift distribution on Mössbauer quadrupole spectra in amorphous magnetic insulators

A mechanism is proposed whereby any distribution of isomer shifts in an amorphous material containing ${\mathrm{Fe}}^{3+}$ will broaden the ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}$ paramagnetic Mössbauer doublet lines. The known variance of isomer shift in amorphous ${\mathrm{Y}}_3$ ${\mathrm{Fe}}_5$ ${\mathrm{O}}_{12}$ is shown to be quite sufficient to account for the observed broadening in this material from that expected for quadrupole energy distribution in a random packed structure.