Chemical bonding and valence state of 3d-metal ions in Ni 1−x Co x Cr 2 O 4 spinels from X-ray diffraction and X-ray photoelectron spectroscopy data

Solvothermal synthesis of Sm3+-doped Fe3O4 nanoparticles

“…At low temperatures, the з+ ratio between Fe2+: Fe3+ should be 1:2 [32]. In [34] the same shoulder in Ni2p3/2 spectrum was explained by the presence of divalent and trivalent nickel ions in N i1-xCoxCr2O4 spinel structure, and the shoulder formed by the contribution from divalent nickel ions. If this approach is applicable to magnetite in respect to the explanation of the shoulder in Fe2p3/2 spectrum, the contribution of Fe ions into total Fe2p spectrum is higher in Sm:MNPs-Bpy than in Sm:MNPs.…”

Valence state of transition metal ions in Co1−Fe Cr2O4 (x= 0.1, 0.2, 0.5) ceramics from X-ray photoelectron and Mössbauer spectroscopy data

“…In the Fe2p-spectrum of Fe 2+ ion calculation gives excessive intensity in the energy region between 2p 3/2 satellite and 2p 1/2 main peak. As discussed in [20], this spectral region contains contributions from the correlation states with excitations of more than one ligand electron. Their contributions seem to be overestimated in our calculation.…”

Crystal structure, composition and valence state of cations in mixed-valence A1−xCdxMnO3 (A=Pr, La) ceramics

“…Table 2 shows that the formula composition determined in x-ray microanalysis demonstrates lower content of cadmium in the Pr 1−x Cd x MnO 3 and La 1−x Cd x MnO 3 samples compared to the XPS data. Factors that determine the difference between the data from XPS and EDS methods in terms of determining elemental compositions are discussed in detail in [34]. Three main factors are pointed out in those works: the difference in the diameters of the electron probe (EDS) and x-ray beam spot diameter (XPS), different depth of analysis, and the fact that during scribing, the surface is destroyed and there are either grain bodies or their boundaries on the surface.…”

“…We believe that in our case, in addition to the first two factors mentioned above, two additional factors can play a significant role in the increased cadmium content based on the XPS data. One of them partially coincides with the third factor mentioned in [34]. In the XPS method, the surface under study is scribed using a diamond file before analysis, until the O1s spectrum contains only a component related to oxygen embedded in the lattice [33][34][35].…”

“…In [17, 25-29, 31, 32], symmetric pseudo-Voigt curves, which are mixtures of Gaussian and Lorentzian curves, were utilized to represent the contributions of the Mn 3+ and Mn 4+ ions when fitting the Mn2p spectra. However, the 2p spectra of transition metals are known to have rather complex asymmetric profiles due to the presence of numerous final states for the transition metal ion after ionization of the 2p level [33][34][35]. Hence, simulating the profiles of the 2p spectra of 3d transition metals with a superposition of symmetric components is not entirely accurate.…”