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Short- and long-range order in La1−xSrxCoO3 and La1−xBaxCoO3 |
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| Authors: | E. Efimova D. Karpinsky J. Purans S. Tiutiunnikov E. Welter V. Simkin |
| Affiliation: | a Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region, Russian Federation b Kurchatov Center for Synchrotron Radiation and Nanotechnology, 123182 Moscow, Russian Federation c Joint Institute of Solid State and Semiconductor Physics, NASB, 220072 Minsk, Belarus d Institute of Solid State Physics, University of Latvia, 8 Kengaraga Street, LV-1063 Riga, Latvia e Berlin Neutron Scatterig Center, HMI, Glienicker Street, 100, Berlin D-14109, Germany f Hamburger Synchrotronstahlungslabor, DESY, Notkestrasse 85, D-22603 Hamburg, Germany g Institute of Nuclear Physics, PAN, ul. Radzikowskiego 152, 31-342 Krakow, Poland h Institute of Crystallography, RWTH, Jaegerstr. 17-19, D-52066 Aachen, Germany |
| Abstract: | The short- and long-range order correlations of the crystal structure in the distorted perovskites La1−xSrxCoO3 and La1−xBaxCoO3 (0.0?x?0.5) have been studied by the neutron powder diffraction (NPD) and the Co K-edge X-ray absorption spectroscopy (XAS) measurements. The results of XAS and NPD indicate a local distortion around the Co3+ ions in LaCoO3 at room temperature. The substitution of the La3+ ions by the Sr2+(Ba2+) ions leads to a gradual increase of the Co-O-Co angle and is accompanied by an increase of the mean square relative displacement (MSRD) of the Co-O bond. These results correlate with an increase of the oxygen amplitude vibration in the direction perpendicular to the Co-O bond. The possible explanation of the observed changes of the crystal and electronic structures in the above-mentioned cobaltites is discussed. |
| Keywords: | Local structure Atomic correlations Cobaltates EXAFS and XANES Neutron diffraction |
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