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Control compositivo de las propiedades superconductoras de LiFeAs
Michael J Pitcher1, Tom Lancaster, Jack D Wright
1Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR, United Kingdom.
Journal of the American Chemical Society
|July 29, 2010
Resumen
Las sustituciones químicas en LiFeAs tienen un impacto significativo en sus propiedades superconductoras. La deficiencia de litio suprime rápidamente la superconductividad, mientras que la sustitución de Co o Ni reduce la temperatura crítica y la rigidez del superfluido, destacando los LiFeAs.
Área de la Ciencia:
- Física de la materia condensada Física de la materia condensada
- Ciencia de los materiales Ciencia de los materiales.
- Química del estado sólido.
Sus antecedentes:
- El arseniuro de litio y hierro (LiFeAs) es un notable superconductor a base de hierro.
- Comprender el impacto del dopaje químico en sus propiedades superconductoras es crucial para el diseño de materiales.
Objetivo del estudio:
- Investigar los efectos de las sustituciones químicas en los sitios de Li y Fe en el estado superconductor y la estructura cristalina de LiFeAs.
- Determinar la sensibilidad de la superconductividad en LiFeAs a cambios de composición y dopaje de electrones.
Principales métodos:
- Los rayos X de alta resolución y la difracción de neutrones.
- La magnetometría es una magnetometría.
- Espectroscopia de rotación de muón-espín.
Principales resultados:
- La deficiencia de litio (Li(1-y) Fe(1+y) As) suprime rápidamente la superconductividad, con una destrucción completa en y > 0,02.
- La sustitución de Fe por Co o Ni disminuye monotónicamente la temperatura de transición superconductora (T ((c)) y la rigidez superfluida (rho ((s)) con el aumento del recuento de electrones.
- La superconductividad se suprime por completo en los niveles más altos de dopaje.
- Los compuestos derivados de LiFeAs exhiben una mayor rigidez superfluida que otros pnictidos de hierro.
Conclusiones:
- La superconductividad en LiFeAs es muy sensible a la composición química y al dopaje.
- Las tendencias observadas en T (c) y rho (s) proporcionan información sobre el mecanismo de emparejamiento en los superconductores a base de hierro.
- LiFeAs tiene una posición única entre los superconductores de pnictide de hierro debido a su alta rigidez superfluida.
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