Temperature-dependent X-ray absorption near edge spectroscopy of doped LaMnO3: Ion-size and the Jahn–Teller distortion effects

Electron Paramagnetic Resonance Analysis of La1–xMxMnO3+δ (M = Ce, Sr) Perovskite-Like Nanostructured Catalysts

“…Concerning the use of these materials as catalysts for hydrocarbon CFC, we must outline also that a satisfactory catalytic performance may be attained at high temperature only because of oxygen mobility through the perovskite-like lattice . On the other hand, tight relationships exist between lattice structure and magnetic and electronic properties of these crystals, , as well as between their defect chemistry and transport properties. Nevertheless, univocal interpretation of these relationships has not been proposed yet.…”

Temperature dependence of the pre-edge structure in the Ti K-edge x-ray absorption spectrum of rutile

“…[15], it was observed at the K-edge of titanium in TiO 2 and Mg 2 TiO 4 [30], at the L-edges of La in Sr-doped La 2 CuO 4 [39] and at the K-edge of V in VO 2 [40]. A temperature dependence of XANES spectra was also observed at the K-edge of oxygen in water [41] and in doped LaMnO 3 [42,43]. Finally, the Mahan-Nozières-Dominics singularity can also give rise to a temperature dependence of the x-ray absorption spectra of metals (see Ref.…”

Polaronic effect in the x-ray absorption spectra of La1−x Ca x MnO3 manganites

“…There are three features that can be identified around 529.2 eV (A 1 ), 529.7 eV (A 2 ), and 531.5 eV (A 3 ) in the T = 19 K spectrum of x = 0.3 sample (these energies depend on doping level x.) These features are associated with dipole transitions to the majority e g (e g↑ ), minority t 2g (t 2g↓ ), and minority e g (e g↓ ) states, respectively (see the schematic energy diagram in figure 3) [35]. By comparing these spectra, one finds that the intensity of A 3 is enhanced dramatically in Mn 4+ rich compound (x = 0.8) and the total integrated intensity in (527.5 eV, 532 eV) energy window is also larger.…”

“…3). [35] By comparing these spectra, one finds that the intensity of A 3 is enhanced dramatically in Mn 4+ rich compound (x = 0.8) and the total integrated intensity in [527.5 eV, 532 eV] energy window is also larger. This observation indicates the stronger covalent bonding between Mn and O orbitals at higher doping level x.…”

“…How does the strength of JTD lead to the temperature dependence of ∆E x that we observed in figure 4(a)? With Ca doping, the magnitude of JTD along with competition between J ex and 10Dq will considerably modify the energy splitting between e g↑ and t 2g↓ states [35,36]. For x = 0.3 sample, local JTD is weakened in FMM state (right panel of figure 3) compared to that in PMI state (left panel of figure 3).…”