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Observación directa de las inhomogeneidades microscópicas con la difracción dispersiva de energía de los rayos X

E F Skelton, A R Drews, M S Osofsky

Science (New York, N.Y.)

|March 11, 1994

Resumen

Se encontraron inhomogeneidades estructurales en los superconductores de alta temperatura de transición YBa(2)Cu(3)O(7-delta) y Nd2-xCexCuO4-y. Estas variaciones en el contenido de oxígeno y cerio desafían la interpretación de resultados experimentales exóticos como propiedades intrínsecas.

Área de la Ciencia:

Ciencia de los materiales Ciencia de los materiales.
Física de la materia condensada Física de la materia condensada
Química del estado sólido.

Sus antecedentes:

Los superconductores de alta temperatura de transición exhiben comportamientos complejos que no se comprenden completamente.
Investigar la integridad estructural de estos materiales es crucial para interpretar sus propiedades físicas.

Objetivo del estudio:

Para investigar la presencia de inhomogeneidades estructurales en YBa(2)Cu(3)O(7-delta) y Nd2-xCexCuO4-y.
Para determinar si las variaciones estructurales detectadas se correlacionan con cambios en la composición elemental.
Evaluar el impacto de estas inhomogeneidades en la interpretación de las propiedades superconductoras.

Principales métodos:

Utilizó una difracción de rayos X altamente colimada basada en sincrotrones.
Las muestras analizadas de YBa(2)Cu(3)O(7-delta) y Nd2-xCexCuO4-y.
Estructuras de celosía examinadas en una escala espacial de 10 micrómetros.

Principales resultados:

Se detectaron pequeños cambios localizados en la red cristalina de ambos tipos de superconductores.
Interpretó estas variaciones en la red como indicativas de un contenido de oxígeno no uniforme en YBa(2)Cu(3)O(7-delta).
Interpretó estas variaciones en la red como indicativas de un contenido de cerio no uniforme en Nd2-xCexCuO4-y.

Conclusiones:

Existen inhomogeneidades estructurales en los superconductores de alta temperatura de transición YBa(2)Cu(3)O(7-delta) y Nd2-xCexCuO4-y.
Estas inhomogeneidades, relacionadas con las variaciones elementales, pueden influir significativamente en las propiedades superconductoras.
La presencia de tales defectos estructurales plantea preguntas sobre la naturaleza intrínseca de los fenómenos exóticos observados en estos materiales.

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