Spin reorientation and magnetization reversal in the perovskite oxides, YFe1−xMnxO3 (0≤x≤0.45): A neutron diffraction study

Abstract

Members of the YFe1−xMnxO3 (0≤x≤0.45) family crystallize in the GdFeO3 type orthorhombic perovskite structure (space group Pnma) where the Fe and Mn ions are disordered at the 4b crystallographic site. Upon substitution of Mn at the Fe-site in the canted antiferromagnetic YFeO3 (TN=640 K), a first-order spin-reorientation transition occurs at a temperature, TSR, where the magnetic structure changes from the canted to a collinear state. With increasing Mn-concentration, TSR increases whereas TN decreases. Neutron diffraction studies on the x=0.4 sample reveal that the spin structure changes from Γ4 to Γ1 below TSR. Intriguingly, when x=0.4 and 0.45, a temperature-induced magnetization reversal is observed below a compensation temperature T⁎ (T⁎<TSR<TN). The reversal is explained on the basis of a ferrimagnetic ground state resulting from antiferromagnetic coupling of the canted moments of Fe–O–Fe and Mn–O–Mn with that of Fe–O–Mn ordering.