Suppression of T-c in the (Y0.9Ca0.1)Ba2Cu4-xFexO8 system
In this paper, the effects produced by iron substitutions in the (Y0.9Ca0.1)Ba2Cu4-xFexO8 system on the Superconducting and structural properties are studied. The Rietveld-fit of the crystal structure and Mossbauer spectroscopy results of (Y0.9Ca0.1)Ba2Cu4-xFexO8 samples indicate that the iron atoms...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2002 |
| País: | México |
| Institución: | Universidad Nacional Autónoma de México |
| Repositorio: | Sistema de Información de la Facultad de Ciencias, UNAM |
| OAI Identifier: | oai:repositorio.fciencias.unam.mx:11154/2516 |
| Acceso en línea: | http://hdl.handle.net/11154/2516 |
| Access Level: | acceso abierto |
| Palabra clave: | Physics, Applied Physics, Condensed Matter |
| Sumario: | In this paper, the effects produced by iron substitutions in the (Y0.9Ca0.1)Ba2Cu4-xFexO8 system on the Superconducting and structural properties are studied. The Rietveld-fit of the crystal structure and Mossbauer spectroscopy results of (Y0.9Ca0.1)Ba2Cu4-xFexO8 samples indicate that the iron atoms occupy the Cu(1) sites of the (Cu-O)(2) double chains in fivefold coordination at low iron concentrations. Besides at high iron concentrations the iron atoms occupy the Cu(I) sites of single Cu-O chains and Cu(2) sites in the CuO2 planes of the (Y0.9Ca0.1)Ba2Cu4O8 phase with structural defects. Simultaneously, as iron concentration increases, a faster decrease of T-c is observed in this material compared with the YBa2Cu3-xFexO7-delta system. According to the charge-transfer model proposed for YBa2Cu4O8 under pressure, the decrease in the Cu(1)-O(4) bond length in parallel to the increase in the Cu(2)-O(4) bond length may affect the charge-transfer mechanism leading to the suppression of T-c. |
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