Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1805195 | Journal of Magnetism and Magnetic Materials | 2007 | 9 Pages |
Abstract
We have studied crystal structure, ionic-model energy calculation, and electron energy-loss spectroscopy (EELS) for a new magnetic ordered-perovskite Sr2Cu(Re0.69Ca0.31)O6 in order to determine oxidation states of the Re and Cu ions. All of the experimental results of the bond-valence sum, the static energies, and the energy-loss near-edge structure (ELNES) in EEL spectra consistently indicated that the Re7+, Cu2+ and Cu3+ valence states are realized in the compound. This is evident that the Cu spins are responsible for the magnetism in the phase. By considering the Cu 3d and O 2p orbital shapes, we concluded that the unusually high Curie temperature, TCâ¼440Â K, originates in ferrimagnetism with strongly coupled Cu spins in a three dimensional (3-D) network of the Cu2+-O-Cu3+-O-Cu2+ bond in structure.
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Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
M. Isobe, Y. Uchida, K. Kimoto, E. Takayama-Muromachi,