1. Temperature Dependent EXAFS Study of Chromium-Doped GaFeO3 at Gallium and Iron Edges
- Author
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Amit Chakrabarti, S. K. Basu, Ripandeep Singh, A. K. Nigam, Debaraj Bhattacharyya, S. N. Jha, A. K. Das, and Tufan Roy
- Subjects
Materials science ,Extended X-ray absorption fine structure ,Transition temperature ,Doping ,Neutron diffraction ,Analytical chemistry ,chemistry.chemical_element ,Dielectric ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Bond length ,Condensed Matter::Materials Science ,Crystallography ,Chromium ,General Energy ,chemistry ,Physical and Theoretical Chemistry ,Gallium - Abstract
We report the results of EXAFS measurements on undoped and Cr-doped GaFeO3 samples both at Ga and Fe K edges at various temperatures in the regime of 25–300 K, to explore the changes in local structure surrounding the cations (viz., Ga and Fe) in GaFeO3 due to Cr substitution and across its magnetic transition temperature. The EXAFS results along with neutron diffraction studies and theoretical simulations establish the mechanism of Cr substitution in the GaFeO3 lattice in a microscopic scale. The decrease in the paramagnetic–ferrimagnetic transition temperature (TC) and the saturation magnetization observed in the samples with increase in Cr doping concentration, has been attributed to the decrease of Fe and concomitant increase of Cr in Ga2 site. The bond lengths at both Fe and Ga sites exhibit changes at the magnetic transition temperatures, indicating enhanced cationic site disorder, which also explains the reported dielectric anomalies observed in these samples at the magnetic transition temperatures.
- Published
- 2015