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Ferromagnético polar a temperatura ambiente ScFeO3 transformado desde una fase de alta presión de perovskita

Takahiro Kawamoto¹, Koji Fujita, Ikuya Yamada

¹Department of Material Chemistry, Graduate School of Engineering, Kyoto University , Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.

Journal of the American Chemical Society

|October 22, 2014

Resumen

Los investigadores sintetizaron un nuevo material ScFeO3 con propiedades tanto ferroeléctricas como magnéticas a temperatura ambiente. Este descubrimiento ofrece una nueva vía para el desarrollo de materiales multiferroicos avanzados para aplicaciones a altas temperaturas.

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:

Los materiales multiferroicos que exhiben propiedades magnéticas y ferroeléctricas a temperatura ambiente son muy buscados, pero son difíciles de sintetizar.
Los materiales multiferroicos existentes a menudo carecen de un rendimiento robusto a temperaturas ambientales.

Objetivo del estudio:

Sintetizar y caracterizar una nueva fase ScFeO3 tipo LiNbO3 con ordenamientos ferroeléctricos y magnéticos coexistentes.
Investigar las propiedades estructurales, magnéticas y ferroeléctricas del material sintetizado.
Establecer una estrategia para la creación de materiales multiferroicos de alta temperatura.

Principales métodos:

Síntesis a alta presión y alta temperatura.
Sincrotrón de rayos X y difracción de polvo de neutrones para el análisis estructural.
Microscopía electrónica de escaneo de transmisión de campo oscuro anular de ángulo alto (HAADF-STEM) para la obtención de imágenes.
Mediciones de la susceptibilidad magnética.

Principales resultados:

Se ha sintetizado con éxito la fase metastable LiNbO3-tipo ScFeO3 con simetría polar R3c.
Se observó una gran polarización espontánea de 100 μC/cm2 a lo largo del eje c hexagonal.
Se identificó un ferromagnetismo débil con una temperatura Néel (TN) de 545 K debido a un ordenamiento antiferromagnético inclinado.
Se estableció una correlación entre TN y el ángulo de enlace Fe-O-Fe, influenciado por el tamaño del catión del sitio A y la inclinación octaédrica.

Conclusiones:

El ScFeO3 de tipo LiNbO3 es el primer ejemplo de su tipo que exhibe ordenamiento magnético muy por encima de la temperatura ambiente.
El estudio proporciona una estrategia versátil para diseñar materiales multiferroicos con ferroelectricidad y ferromagnetismo coexistentes a altas temperaturas.
La inclinación octaédrica, controlada por el tamaño del catión del sitio A, juega un papel crucial en la transición magnética a través de interacciones de superecambio.

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