Electronic structure of Pr_x La_1‐xAlO₃ solid solution

Abstract

The crystals of Prx La1−xAlO3 solid solution grown by the Czochralski method were examined by X‐ray photoelectron spectroscopy. The electric conductivity was measured at high temperature range. The composition of the Prx La1−xAlO3+xcrystals obtained with XPS analysis exhibited an increased content of oxygen in comparison to the nominal value. The praseodymium valence may influence the coloration of the Prx La1−xAlO3 crystals. In the dark brown colour Pr0.40La0.60AlO3 sample with the highest amount of oxygen the 3d4f1 satellite lines have the highest intensity and were attributed to presence of Pr4+ ions. The semiconducting properties of the Prx La1−xAlO3 single crystals correspond to the electronic structure determined with the XPS measurements and to the deduced occurrence of defects. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Effects of state filling and localization on chemical expansion in praseodymium-oxide perovskites

“…These 4f 3 L̲ peaks (where L̲ indicates a hole on oxygen) have been attributed to strong covalent mixing between Pr and O ions. 51,52…”

“…These 4f 3 L peaks (where L indicates a hole on oxygen) have been attributed to strong covalent mixing between Pr and O ions. Determination of quantitative Pr 3+ /Pr 4+ ratios from the XPS data requires tting; however, the multiple strategies reported in the literature for this purpose [52][53][54] return different results (see ESI Note 1 for further details). † Therefore, we restrict our analysis to only a qualitative comparison between our materials and the reference oxides as follows: compared to Pr 2 O 3 and Pr 6 O 11 , the main 3d 5/2 and 3d 3/2 peaks are shied to higher energies in PGM and BPY, consistent with the observations in other mixed Pr oxides.…”

Facile Synthesis of Ca-Doped LaCoO3Perovskite via Chemically Assisted Electrodeposition as a Protective Film on Solid Oxide Fuel Cell Interconnects

“…23,30,31 The La 3d XPS spectrum (Figure 4b) has two spin-orbit components of La 3d 5/2 and La 3d 3/2 , each of which exhibits a double-peak structure (BE = 833.1 eV and 837.1 eV for La 3d 5/2 and BE = 849.9 eV and 853.9 eV for La 3d 3/2 ) associated with electron transfer from oxygen ligands to La 4f. [32][33][34] Two main peaks for Ca 2p 3/2 (BE = 346.3 eV) and Ca 2p 1/2 (BE = 350.2 eV) are seen in the Ca 2p XPS spectrum (Figure 4c). The La 3d and Ca 2p XPS spectra shown in Figures 4b and 4c are in good agreement with the data reported for perovskite oxides elsewhere, [31][32][33][34] indicating that the La and Ca in the LCCO film are present in trivalent La 3+ and divalent Ca 2+ states, respectively.…”

“…[32][33][34] Two main peaks for Ca 2p 3/2 (BE = 346.3 eV) and Ca 2p 1/2 (BE = 350.2 eV) are seen in the Ca 2p XPS spectrum (Figure 4c). The La 3d and Ca 2p XPS spectra shown in Figures 4b and 4c are in good agreement with the data reported for perovskite oxides elsewhere, [31][32][33][34] indicating that the La and Ca in the LCCO film are present in trivalent La 3+ and divalent Ca 2+ states, respectively.…”