Synthesis, cation distribution and crystal structure of the spinel oxides MnGaxFe1−xCrO4 by neutron diffraction

The spinel system MnGaxFe1−xCrO4 (x=0.0, 0.25, 0.50, 0.75 and 1.0) was prepared by the solid state sintering method in air at 1523 K. X-ray and neutron powder diffraction measurements were performed on the samples at 295 K for structural characterization. Rietveld refinement of the neutron diffraction data revealed that all the samples of the series possessed cubic symmetry corresponding to the space group Fd3m. The distributions of the four cations Mn, Ga, Fe and Cr over the two sublattices and other crystallographic parameters were found. The lattice constant showed a decrease with increasing Ga content in the system. The magnetic structure at room temperature was found to be ferrimagnetic in the composition range x⩽0.50.