A Three-Sublattice Theory of Weakly Ferromagnetic α-M4+δFe2+δFe3+ 2(1−δ)O3

Abstract

A model of α‐M⁴⁺_δ Fe²⁺_δ Fe³⁺_2(1−δ)O₃ has been developed in which the ensemble of ferrous ions is treated as a third sublattice coupled to the two ferric sublattices. By assuming that the ferrous sublattice is highly damped and that it couples antiferromagnetically to the two ferric sublattices, it is found that the model consistently describes the magnetic resonance data on hematite doped with tetravalent ions. The effect of the third sublattice on the spontaneous magnetization and other properties is discussed.