Low-temperature spin-state transition in LaCoO{sub 3} investigated using resonant x-ray absorption at the Co K edge
- Laboratory for Developments and Methods, Paul Scherrer Institute, 5232 Villigen PSI (Switzerland)
- INFM, Dipartimento di Fisica, Politecnico di Milano, piazza Leonardo da Vinci 32, 20133 Milano (Italy)
- Institut de Physique des Nanostructures, Ecole Polytechnique Federale, 1015 Lausanne (Switzerland)
- Laboratory for Neutron Scattering, ETH Zurich and PSI, 5232 Villigen PSI (Switzerland)
- European Synchrotron Radiation Facility, Boite Postale 220, 38043 Grenoble Cedex (France)
- Laboratory of Materials and Semiconductor Physics, Royal Institute of Technology, Electrum 229, S-164 40 Kista (Sweden)
- Institute of Solid State and Semiconductor Physics, National Academy of Science, Minsk 220072 (Belarus)
LaCoO{sub 3} displays two broad anomalies in the DC magnetic susceptibility {chi}{sup DC}, occurring, respectively, around 50 K and 500 K. We have investigated the first of them within the 10 K<T<RT temperature range using Co K{alpha}{sub 1} x-ray absorption spectroscopy (XAS) in the partial fluorescence yield mode. In contrast with previous O K-edge XAS reports, our data show the existence of abrupt changes around 50 K which can be nicely correlated with the anomaly in {chi}{sup DC}. To our knowledge, this is the first time that a clear, quantitative relationship between the temperature dependence of the magnetic susceptibility and that of the XAS spectra is reported. The intensity changes in the preedge region, which are consistent with a transition from a lower to a higher spin state, have been analyzed using a minimal model including the Co 3d and O 2p hybridization in the initial state. The temperature dependence of the Co magnetic moment obtained from the estimated e{sub g} and t{sub 2g} occupations could be satisfactorily reproduced. Also, the decrease of the Co 3d and O 2p hybridization by increasing temperature obtained from this simple model compares favorably with the values estimated from thermal evolution of the crystallographic structure.
- OSTI ID:
- 20787910
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 73, Issue 5; Other Information: DOI: 10.1103/PhysRevB.73.054424; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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