Some optical characteristics of powdered tellurites of rare-earth elements
| Autor: | L. A. Ivanchenko, A. L. Voloshina, E. S. Lugovskaya, V. A. Obolonchik |
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| Rok vydání: | 1982 |
| Předmět: |
Materials science
Photon Birefringence Condensed matter physics business.industry Rare earth Isotropy Metals and Alloys Condensed Matter Physics Symmetry (physics) law.invention Semiconductor Optics Mechanics of Materials law Materials Chemistry Ceramics and Composites Crystallization business Refractive index |
| Zdroj: | Soviet Powder Metallurgy and Metal Ceramics. 21:728-731 |
| ISSN: | 1573-9066 0038-5735 |
| DOI: | 10.1007/bf00806798 |
| Popis: | As a result of the crystallization of La tellurite specimens accompanying the raising of heat treatment temperature, the refractive index of the compound increases, isotropic particles with cubic structure symmetry become replaced by grains of long prismatic shape, birefringence appears, and the refractive index becomes dependent on orientation. Judged by the character of their reaction with light, compounds of the Ln2Te3O9 type may be classed as semiconductors with forbidden zone of widths hυ 0≥3.8 eV. It is shown, taking La2Te3O9 as an example, that the heat treatment of air-dry specimens at temperatures above 400°C reduces the width of the forbidden zones of the compounds investigated and increases their light absorption coefficients at photon energies hυ 4 eV. |
| Databáze: | OpenAIRE |
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