Cation distribution and valence state of copper ferrites Cu1−δFe2+δO4

Abstract

The equilibrium cation distribution and the valence state on tetrahedral or octahedral sites in copper ferrites Cu_1−δFe_2+δO₄ have been derived by taking account of site exchange not only of cationic nuclei but also of valence electrons. The calculated cation distribution has shown satisfactory agreement with experimental results for the composition range δ?0.5. Two nonequilibrium valence states accompanied by the transposition of valence electrons from the equilibrium sites were expected and they corresponded well to the positive and negative regions in the observed Seebeck coefficient of quenched Cu_1−δFe_2+δO₄.