A.V. Nikolskii

X-Ray-induced low-energy electron emission from solids (one-dimensional theoretical model)

Abstract The effect of the solid surface on the X-ray induced low-energy electron emission is analysed, using the formalism of the general scattering theory, by means of an approach, called by us the ‘diagonalisation method’. Explicit analytical expressions and numerical results, obtained in the one-dimensional approximation, show great sensitivity of the shape of electron emission spectra near the threshold to the surface potential barrier height and to the presence of the amorphous ‘transition’ layer.

Effect of sintering temperature on the chemical state of ions in the Ba1 − xSrxTiO3 (x = 0.2) system, according to X-ray photoelectron spectroscopy data

The chemical state of ions in different samples of ceramics of the Ba1 − xSrxTiO3 (x = 0.2) system produced by varying only a single technological parameter (sintering temperature TS) is studied by means of X-ray photoelectron spectroscopy. The X-ray electron spectra of the Ba4d, Sr3d, O1s, and Ti2p levels reveal well-marked fine structures. As expected, the energy position and intensity of the features of this fine structure vary with TS.

Crystal Structure, Phase and Elemental Composition and Chemical Bonding in Bi 1− X A X FeO 3± Y Systems ( A = Sr, Ca; 0 ≤ X ≤ 1) from X-ray Diffraction, Mössbauer, and X-ray Photoelectron Spectra

An integrated study of samples of Bi1−x A x FeO3±y (A = Sr, Ca) systems for 0 ≤ x ≤ 1 (step 0.1) is performed using X-ray diffraction (XRD), Mossbauer spectroscopy (MS), and X-ray photoelectron spectroscopy (XPS). Considerable deviations of actual elemental compositions from nominal ones in the samples of both systems are discovered. Both Fe3+ and Fe4+ ions are found to be present in the samples of the Bi1−x Sr x FeO3±y system with x > 0. No Fe4+ ions are discovered upon substitution of Bi3+ by Ca2+ in Bi1−x Ca x FeO3±y , neither by Mossbauer spectroscopy, nor by XPS. Charge compensation in Bi1−x Ca x FeO3±y takes place mostly via creation of oxygen vacancies.

Valence state and X-ray photoelectron 2 p spectra of chromium ions in the La 1– x Sr x CrO 3 ( x = 0, 0.1, 0.3, 0.5) system

Room-temperature Cr2p X-ray photoelectron spectra of samples of the La1–xSrxCrO3 system with x = 0, 0.1, 0.3, and 0.5 are obtained. The profiles of these spectra vary considerably with x. XPS analysis shows that the chromium ions are in a mixed valence state. The introduction of Sr2+ ions into the lattice is compensated for by the mechanism of Cr3+, Cr4+, Cr5+, and Cr6+ ion formation. Decomposition of Cr2p3/2 spectra into components with profiles corresponding to Cr3+, Cr4+, Cr5+, and Cr6+ ions has shown that the contribution from Cr6+ ions grows along with with x in the Cr2p3/2 spectra, while the contribution from Cr3+, Cr4+, and Cr5+ ions is reduced at higher x values.

Determining the valence state of manganese ions in complex oxides La1–xCaxMnO3 (x = 0.5, 0.7, 0.85, and 0.9) based on Mn2p and Mn3s X-ray photoelectron spectra

The valence state of manganese ions in complex oxides La1–xCaxMnO3 (x = 0.5, 0.7, 0.85, and 0.9) is studied on the basis of Mn2p and Mn3s X-ray photoelectron spectra. It is shown that manganese ions have the valence of Mn3+ and Mn4+ in the studied compounds. The relative Mn3+/Mn4+ content is determined.

Fine structure of the X-ray photoelectron Ni 2p spectrum in Ni1–xCoxCr2O4 compounds

An interpretation of the components of the fine structure of X-ray photoelectron Ni

Single-crystal rare earths manganites La1−x−yBixAyMnαO3±β (A = Ba, Pb): Crystal structure, composition, and Mn ions valence state. X-ray diffraction and XPS study

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Valence state of transition metal ions in Co1−xFexCr2O4 (x = 0.1, 0.2, 0.5) ceramics from X-ray photoelectron and Mössbauer spectroscopy data

spectra of Ni1–xCoxCr2O4 solid solutions (x = 0.8, 0.5, 0.3, 0.02, 0.01, 0.005, 0.0) is given. It is shown that the A and B components of the fine structure in Ni