Low-Temperature Schottky Anomalies and the Magnetic State of the p Electrons of Oxygen in Substituted Gd0.4Sr0.6CoO3 – δ Cobaltites

The XANES spectra (X-ray absorption near-edge spectra) at the K edge of Co and the L 3 edge of Gd in polycrystalline Gd 0.4 Sr 0.6 CoO 3 – δ rare-earth oxides with an ordered and disordered distribution of Gd 3+ and Sr 2+ cations over the A sites in the crystal lattice are measured. The results of X...

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Bibliographic Details
Published in:Journal of experimental and theoretical physics 2018-02, Vol.126 (2), p.217-223
Main Authors: Orlov, Yu. S., Dudnikov, V. A., Platunov, M. S., Gorev, M. V., Velikanov, D. A., Kazak, N. V., Gavrilkin, S. Yu, Solov’ev, L. A., Veligzhanin, A. A., Vereshchagin, S. N., Ovchinnikov, S. G.
Format: Article
Language:English
Subjects:
Absorption
Anomalies
Classical and Quantum Gravitation
Cobalt compounds
Crystal lattices
Disorder
Electrons
Elementary Particles
Gadolinium
Low temperature
Order
Oxygen
Particle and Nuclear Physics
Phase Transition in Condensed System
Physics
Physics and Astronomy
Polycrystals
Quantum Field Theory
Rare earth compounds
Relativity Theory
Single crystals
Solid State Physics
Specific heat
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Summary:The XANES spectra (X-ray absorption near-edge spectra) at the K edge of Co and the L 3 edge of Gd in polycrystalline Gd 0.4 Sr 0.6 CoO 3 – δ rare-earth oxides with an ordered and disordered distribution of Gd 3+ and Sr 2+ cations over the A sites in the crystal lattice are measured. The results of XANES measurements do not reveal a noticeable shift in the absorption edge with increasing Sr concentration as compared to the GdCoO 3 parent composition. The measured temperature dependences of the heat capacity of polycrystalline ordered and disordered samples and a single-crystal ordered Gd 0.4 Sr 0.6 CoO 2.85 sample exhibit two Schottky anomalies. These anomalies are thought to be related to the high-spin state of the Co 3+ ions in the pyramidal environment caused by oxygen deficiency and to the magnetic state of oxygen p electrons induced by the doping-assisted generation of a hole in the 2 p state. The absence of a noticeable shift in the absorption edge and the presence of two Schottky anomalies support the fact that the charge state of cobalt remains unchanged in the compounds under study.
ISSN:1063-7761
1090-6509
DOI:10.1134/S1063776118020036