Structural characterization of SrLaMnRuO 6 by synchrotron X-ray powder diffraction and X-ray absorption spectroscopy

Abstract

Single-phase polycrystalline powder samples of SrLaMnRuO 6 were prepared by solid-state synthesis method and its crystal structure was studied using synchrotron X-ray diffraction and X-ray absorption spectroscopies. The Rietveld analysis of the room temperature synchrotron X-ray diffraction data shows that it has a double perovskite structure with disordered arrangements of Sr/La and Mn/Ru and adopts orthorhombic space group Pbnm [ a = 5.5004(3) Å, b = 5.5445(3) Å, c = 7.7713(5) Å, V = 237.00(3) Å 3]. The X-ray absorption near edge spectra (XANES) show that both Mn and Ru occupy octahedral sites in agreement with the synchrotron X-ray diffraction measurements and that the oxidation state of Mn is +3. Extended X-ray absorption fine structure (EXAFS) analyses of Mn K edge spectra showed that the local order around Mn/Ru can be described as distorted Mn/RuO 6 octahedra with three different Mn/Ru–O bond lengths. The local structure as determined from EXAFS is in good agreement with the average structure determined from synchrotron X-ray diffraction measurements.