Study of local distortion and spin reorientation in polycrystalline Mn doped GdFeO3

The present work reports preparation of polycrystalline GdFe1−xMnxO3 (x = 0.0 to 0.5) samples with solid-state reaction method and characterization using x-ray diffraction, 57Fe Mössbauer spectroscopy, magnetization measurements, leakage current density and soft x-ray absorption spectroscopy measurements. Although Fe3+and Mn3+ have similar ionic radii, noticeable variations in lattice parameters are seen which are attributed to local distortions introduced by Jahn-Teller active Mn3+ doping. Antiferromagnetic transition temperature corresponding to Fe3+ ordering (TN,Fe) and Gd3+ ordering (TN,Gd) is found to decrease with Mn doping, which could be due to weakening of Fe-Fe interaction and Gd-Gd interactions respectively. The Mn substitution at Fe site in GdFeO3 is found to induce Fe3+ spin reorientation transition (TSRT) at a critical concentration and TSRT is found to increase with the Mn doping. Temperature dependent 57Fe Mössbauer measurements have been carried out to study the local distortions by estimating quadrupole shift, the evolution of magnetism and also the spin reorientation transition in GdFeO3 with Mn doping. Leakage current density is found to increase with Mn doping in GdFeO3, initially very fast and almost saturating for higher concentrations of Mn doping due to the formation of multiple oxidation states of dopant Mn at lower concentrations as evidenced from soft x-ray absorption spectroscopy measurements.