Microstructural, spectroscopic and optical studies of the monophosphates Ba(M0.50Nb0.50)(PO4)2 with M = Fe and In

Two orthophosphates Ba(M0.50Nb0.50)(PO4)2 with (M = Fe and In) of the Yavapaiite type structure, were prepared by solid-state reaction in the atmosphere. The structure of these phases was determined, in the space group C2/m, at room temperature from X ray powder diffraction using the Rietveld method. The Infrared and Raman spectra recorded at room temperature revealed characteristic bands of the PO43- tetrahedra and (Nb/M)O6 octahedra groups. The morphology and chemical composition of these compounds were studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The obtained optical gap energies values for the studied phosphates (2.93 eV [Fe] and 3.28 eV [In]), indicating them as semi-conducting materials.