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El control del ordenamiento magnético por las distorsiones de Jahn-Teller en Nd{2) GaMnO{6) y La{2) GaMnO{6)
E J Cussen1, M J Rosseinsky, P D Battle
1Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, UK.
Journal of the American Chemical Society
|July 18, 2001
Resumen
La sustitución de galio en las perovskitas LaMnO ((3) y NdMnO ((3) altera la estructura cristalina y el ordenamiento magnético. La ((2) GaMnO ((6) se convierte en un aislante ferromagnético, mientras que Nd ((2) GaMnO ((6) exhibe un antiferromagnetismo inclinado complejo debido a los efectos de Ga ((3+) en las distorsiones de Jahn-Teller.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Física del estado sólido Física del estado sólido
- La cristalografía es una técnica de cristalografía.
Sus antecedentes:
- Las manganitas de perovskita como LaMnO3 y NdMnO3 exhiben distorsiones de Jahn-Teller y antiferromagnetismo.
- La sustitución de cationes puede ajustar significativamente sus propiedades estructurales y magnéticas.
Objetivo del estudio:
- Investigar los efectos de la sustitución de Ga3+) en la estructura cristalina y el ordenamiento magnético de LaMnO3 y NdMnO3.
- Para caracterizar las fases magnéticas resultantes, incluidos los arreglos ferromagnéticos y antiferromagnéticos inclinados.
Principales métodos:
- Síntesis y caracterización de las nuevas fases de perovskita La(2) GaMnO(6) y Nd(2) GaMnO(6).
- Difracción de polvo de neutrones para la determinación del momento estructural y magnético.
- Magnetometría para medir propiedades magnéticas como la temperatura de Curie y los momentos ordenados.
Principales resultados:
- La ((2) GaMnO ((6) se forma como un aislante ferromagnético (T ((c) = 70 K) con distorsiones de Jahn-Teller coherentes suprimidas pero con distorsiones incoherentes significativas.
- Nd(2) GaMnO(6) adopta una estructura de perovskita con una distorsión de Jahn-Teller en modo Q(2), reducida en magnitud por Ga(3+).
- Nd(2) GaMnO(6) muestra una estructura antiferromagnética inclinada compleja con momentos Mn(3+) acoplados ferromagnéticamente y momentos Nd(3+) ordenados.
Conclusiones:
- La sustitución de Ga ((3+) tiene un profundo impacto en la interacción entre la estructura cristalina, las distorsiones de Jahn-Teller y el ordenamiento magnético en estas perovskitas.
- Los efectos específicos de Ga3+ difieren entre La2GaMnO6 y Nd2GaMnO6, lo que lleva a comportamientos magnéticos distintos.
- Comprender estas relaciones estructura-propiedad es crucial para diseñar nuevos materiales magnéticos.
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