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Expansión Térmica Negativa Sintonizable en Compuestos de Nd₂Co₁₇ Sustituidos con Fe/Cr mediante Acoplamiento

Jiayuan Li^1,2, Chenfei Qv², Haoran Tu¹

¹Center for Neutron Scattering and Advanced Light Source Science and Technology, Dongguan University of Technology, Dongguan, P. R. China.

Advanced science (Weinheim, Baden-Wurttemberg, Germany)

|January 23, 2026

Resumen

Desarrollamos un nuevo método magnetoelástico para controlar la expansión térmica en compuestos intermetálicos de tierras raras. Este enfoque permite una expansión térmica sintonizable positiva y negativa (NTE) para aplicaciones de alta precisión.

Área de la Ciencia:

Ciencia de Materiales
Física de la Materia Condensada
Magnetismo

Sus antecedentes:

La expansión térmica sintonizable con precisión es fundamental para aplicaciones de alta precisión.
Lograr la conmutación bidireccional entre expansión térmica positiva y negativa (NTE) a través del control de la composición sigue siendo un desafío.

Objetivo del estudio:

Presentar un enfoque magnetoelástico para adaptar la expansión térmica anisotrópica en compuestos de Nd2(Co1-xFex)17-yCry.
Investigar la conmutación dependiente de la composición entre expansión térmica positiva y negativa.

Principales métodos:

Se utilizó difracción de rayos X de sincrotrón para estudiar la respuesta de la red.
Se realizó un ajuste composicional de los compuestos Nd2(Co1-xFex)17-yCry.
Se realizaron análisis de exponentes críticos cerca de la temperatura de Curie (TC).

Principales resultados:

Las composiciones ricas en Fe exhibieron NTE uniaxial a lo largo del eje c (αc = -5.23 × 10^-6 K^-1) por debajo de TC.
Este NTE se atribuye a un fuerte acoplamiento magnetoelástico y a interacciones de intercambio negativas mejoradas.
El ajuste composicional suprimió el coeficiente de expansión volumétrica y moduló TC (442–625 K).

Conclusiones:

Se estableció una nueva estrategia para lograr una expansión térmica cero o cercana a cero en intermetálicos de tierras raras.
Estos materiales muestran una gran promesa para aplicaciones de gestión térmica de precisión.
Los hallazgos resaltan el papel del acoplamiento magnetoelástico y las interacciones magnéticas en el control de la expansión térmica.

Palabras clave:

expansión térmica controlable transición de fase magnética acoplamiento magnetoelástico

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