Reitveld refined X-ray diffraction patterns for the samples LaCo1−xNixO3 (0 ≤ x ≤ 0.5). In each panel, solid squares represent observed data; the line shows the calculated profile. The difference between the observed and the calculated pattern is shown at the bottom.
Schematic presentation of LaCo(Ni)O3 unit cell.
(a). The electrical resistivity of LaCo1−xNixO3 (0 ≤ x ≤ 0.5), (b) plots of ln ρ vs T−1/2. The inset shows a plot of ln ρ vs T−1 for x = 0 and 0.1.
(a) The hybridization of d-levels of the TM ions and p-levels of the ligand leading to the repulsion of levels and splitting of t2g and eg-levels, (b) the system is insulating (top) as long as the Fermi energy (EF) lies within the localized states (shaded regions), when the mobility edge passes the Fermi energy (centre), the system shows metallic behaviour (bottom).
XANES spectra for the O K-edge of LaCo1−xNixO3 (0 ≤ x ≤ 0.5). The arrows depict the continuous increase in intensity of feature “a” and simultaneous decrease in that of “b” with substitution.
XANES spectra for the Co K-edge of LaCo1−xNixO3 (0 ≤ x ≤ 0.5). No edge shift observed indicating +3 valance state of Co in all compositions.
XANES spectra for the Ni K-edge of LaCo1−xNixO3 (0.1 ≤ x ≤ 0.5). No edge shift observed indicating +3 valance state of the Ni in all compositions.
XANES spectra at the La M5,4 edge of LaCo1−xNixO3 (0.1 ≤ x ≤ 0.5). Spectra confirm +3 valance state of La in all compositions.
Unit cell and electrical transport parameters for LaCo1−xNixO3 (0 ≤ x ≤ 0.5) samples.
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