Revealing the Cu2+ ions localization at low symmetry Bi sites in photorefractive Bi12GeO20 crystals doped with Cu and V by high frequency EPR
| Autor: | Etienne Goovaerts, Mariana Stefan, Sergiu V. Nistor, François Ramaz, Bernard Briat |
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| Rok vydání: | 2015 |
| Předmět: |
Nuclear and High Energy Physics
Physics Biophysics chemistry.chemical_element Condensed Matter Physics Biochemistry Copper Spectral line Ion law.invention Crystal Chemistry Crystallography Paramagnetism chemistry law Condensed Matter::Superconductivity Condensed Matter::Strongly Correlated Electrons Anisotropy Electron paramagnetic resonance Biology Hyperfine structure |
| Zdroj: | Journal of magnetic resonance |
| ISSN: | 1090-7807 |
| DOI: | 10.1016/j.jmr.2015.07.009 |
| Popis: | The sites of incorporation of Cu2+ impurity ions in Bi12GeO20 single crystals co-doped with copper and vanadium have been investigated by electron paramagnetic resonance (EPR). While the X-band EPR spectra consist of a simple broad (Delta B similar to 50 mT) line with anisotropic lineshape, the W-band EPR spectra exhibit well resolved, strongly anisotropic lines, due to transitions within the 3d(9)-D-2 ground manifold of the Cu2+ ions. The most intense group of lines, attributed to the dominant Cu2+(I) center, displays a characteristic four components hyperfine structure for magnetic field orientations close to a < 110 > direction. The g and A tensor main axes are very close to one of the 12 possible sets of orthogonal < 1-10 >, < 00-1 > and < 110 > crystal directions. Several less intense lines, with unresolved hyperfine structure and similar symmetry properties, mostly overlapped by the Cu2+(I) spectrum, were attributed to Cu-2 (+)(II) centers. The two paramagnetic centers are identified as substitutional Cu2+ ions at Bi3+ sites with low C-1 symmetry, very likely resulting from different configurations of neighboring charge compensating defects. (C) 2015 Elsevier Inc. All rights reserved. |
| Databáze: | OpenAIRE |
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