Quantification of Cr in Lu1-xSrxFe0.5Cr0.5O3 (0 ≤ x ≤ 1) samples containing impurities using X-ray techniques in combination with several data treatment methodologies

Abstract

Wet chemical method was applied with the intention of obtaining Lu1-xSrxFe0.5Cr0.5O3 (0 ≤ x ≤ 1) perovskites in polycrystalline form. A systematic study of the crystal structure of the main perovskite phase obtained as well as a characterization of impurities was performed by X-ray techniques: powder diffraction (PXRD), high resolution emission spectroscopy (HR-XES), and photoelectron spectrometry (XPS). The PXRD data of Lu1-xSrxFe0.5Cr0.5O3 (0 ≤ x ≤ 1) were refined using Pbnm orthorhombic unit cell for the perovskite structure. Only samples with x = 0 and x = 0.1 resulted pure; as the amount of Sr increases, it is segregated as impurities, first as SrCrO4 and then as SrFe12O19. The mean oxidation state of Cr in the analyzed samples was obtained from HR-XES by quantifying spectral changes in the Cr-Kβ" and Cr-Kβ2,5 regions by different methodologies: statistical parameters and multivariate methods. The results were compared with the ones obtained by PXRD and XPS. With the last technique Cr6+ ionic concentrations were obtained through the spectral analysis in the region Cr2p3/2–580eV. Similar Cr6+ ionic compositions were obtained using the three X-ray techniques.