Evidence of the Anomalous Charge StateFe4+57in the Nuclear Decay ofCo3+57

Abstract

The first observation of the elusive ${\mathrm{Fe}}^{4+}$ charge state coming from the nuclear decay of ${}_{}{}^{57}{}_{}{}^{}\mathrm{Co}_{}^{3+}{}_{}{}^{}$ has been found in the Mössbauer emission spectra of ${}_{}{}^{57}{}_{}{}^{}\mathrm{Co}$:${\mathrm{La}}_2$ ${\mathrm{Li}}_{0.5}$ ${\mathrm{Co}}_{0.5}$ ${\mathrm{O}}_4$. A Ti-doped sample was prepared in order to show that the ${\mathrm{Fe}}^{4+}$ fraction can be conveniently monitored. Both results were predicted on the basis of the electronic energy-band scheme of these oxides.