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Imán de alta entropía que permite expansiones térmicas distintivas en compuestos intermetálicos

Jinghan Li¹, Kun Lin¹, Hankun Xu¹

¹Beijing Advanced Innovation Center for Materials Genome Engineering, and Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China.

Journal of the American Chemical Society

|October 24, 2024

Resumen

Introducimos imanes de alta entropía (HEM) mediante la integración de diversos compuestos magnéticos. Este nuevo enfoque da como resultado propiedades magnéticas únicas y una expansión térmica cercana a cero en los compuestos intermetálicos Kagome.

Área de la Ciencia:

Ciencias de los materiales
Física de la materia condensada
El magnetismo

Sus antecedentes:

La estrategia de alta entropía se utiliza cada vez más para los materiales funcionales.
Los imanes de alta entropía (HEM) integran diversos compuestos magnéticos en una sola fase.
Se espera que los HEM exhiban propiedades magnéticas únicas.

Objetivo del estudio:

Introducir y ejemplificar el concepto de imanes de alta entropía (HEM).
Investigar las propiedades de expansión magnética y térmica de los HEM.
Explorar el potencial de los HEM para nuevas funcionalidades de los materiales.

Principales métodos:

Compuestos intermetálicos Kagome en capas de tipo AB2 sintetizados con una composición de alta entropía.
Las transiciones magnéticas investigadas mediante mediciones dependientes de la temperatura.
Análisis de las propiedades de expansión térmica en un amplio rango de temperatura.

Principales resultados:

Transiciones magnéticas intrincadas observadas debido a estados magnéticos competidores y interacciones de sitios de alta entropía.
Se han demostrado transformaciones inusuales en la expansión térmica (positiva, cero, negativa).
Se logra una expansión térmica cercana a cero (αv = -0,62 × 10^-6 K^-1) desde 10-360 K en (Ti1/5Zr1/5Hf1/5Nb1/5Fe1/5) Fe2.

Conclusiones:

La estrategia HEM permite la creación de materiales con comportamientos magnéticos complejos.
La expansión térmica cercana a cero se logra en una composición específica de HEM, vinculada a la dinámica del momento magnético.
Los HEM ofrecen una vía prometedora para descubrir nuevos materiales sólidos funcionales.

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