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Gran efecto Hall anómalo en una aleación de alta entropía CoCrFeNiGa ferromagnética a temperatura ambiente
Rajeswari Roy Chowdhury1, Natalia F Shkodich2, Tufan Roy3,4
1Department of Physics, University of South Florida, Tampa, Florida 33620, United States.
ACS nano
|September 3, 2025
Resumen
Introducimos el CoCrFeNiGa nanocristalino, una aleación magnética de alta entropía a temperatura ambiente (HEA, por sus siglas en inglés). Este material exhibe propiedades magnéticas suaves y un gran efecto Hall anómalo, lo que lo hace prometedor para dispositivos espintrónicos robustos.
Área de la Ciencia:
- Ciencias de los materiales
- Física de la materia condensada
- Nanotecnología
Sus antecedentes:
- Las aleaciones de alta entropía (HEAs) ofrecen una combinación única de propiedades magnéticas y mecánicas para aplicaciones avanzadas.
- El desarrollo de HEAs magnéticos a temperatura ambiente es crucial para los dispositivos espintrónicos de próxima generación que requieren resistencia en condiciones extremas.
Objetivo del estudio:
- Introducir el CoCrFeNiGa nanocristalino como un candidato de HEA magnético a granel a temperatura ambiente.
- Para aclarar las propiedades magnéticas y electrónicas de CoCrFeNiGa.
- Evaluar su potencial para aplicaciones espintrónicas.
Principales métodos:
- Caracterización estructural utilizando difracción de rayos X para determinar la composición de fase y el tamaño de la cristallita.
- Las mediciones de propiedades magnéticas, incluida la temperatura de Curie (TC) y la coercitividad.
- Mediciones de la resistividad eléctrica para comprender los mecanismos de transporte de carga.
- Mediciones del efecto Hall anómalo (AHE) para cuantificar su magnitud y dependencia de la temperatura.
Principales resultados:
- CoCrFeNiGa exhibe fases mixtas de BCC y FCC con un tamaño de cristal de ~51 nm.
- Se observó una alta temperatura de Curie (TC ~872 K) y un comportamiento magnético suave.
- La congelación del espín por debajo de 60 K sugiere interacciones magnéticas competidoras.
- El comportamiento metálico con contribuciones de magnon fue confirmado por la resistividad eléctrica.
- Se detectó un efecto Hall anómalo significativo, con contribuciones intrínsecas, que persiste a temperatura ambiente.
Conclusiones:
- El CoCrFeNiGa nanocristalino es un HEA magnético prometedor a temperatura ambiente.
- Su combinación de magnetismo suave, alto TC y gran AHE intrínseco lo hace adecuado para dispositivos espintrónicos robustos.
- Las propiedades del material sugieren potencial para aplicaciones que requieren resistencia en condiciones exigentes.
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