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Rotación rápida de Faraday en las nanopartículas magnéticas de óxido de hierro por luz visible y pulsada en
Shin-Ichi Ohkoshi1, Kenta Imoto1, Asuka Namai1
1Department of Chemistry, School of Science , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku , Tokyo 113-0033 , Japan.
Journal of the American Chemical Society
|January 16, 2019
Resumen
Los nanomateriales magnéticos sintetizados químicamente exhiben magnetismo sensible a la luz. La luz visible desencadena la inversión de la magnetización, mientras que la luz de terahertz (THz) induce efectos magnetoópicos ultrarrápidos para su uso potencial en dispositivos magnéticos avanzados.
Área de la Ciencia:
- Química del espín
- Ciencias de los materiales ópticos
- El nanomagnetismo
Sus antecedentes:
- El magnetismo sensible a las ondas luminosas o electromagnéticas es un área clave en la química del espín y la ciencia de los materiales ópticos.
- El desarrollo de materiales con propiedades magnéticas controlables a través de estímulos externos es crucial para las tecnologías de próxima generación.
Objetivo del estudio:
- Investigar la inversión de la magnetización inducida por la luz y los efectos magnetoópticos ultrarrápidos en nanomateriales magnéticos basados en óxido de hierro ε.
- Explorar las aplicaciones potenciales de estos materiales en memoria magnética de alta densidad y dispositivos magnéticos de alta velocidad.
Principales métodos:
- Síntesis química de las películas ε-Fe2O3 (GTC-ε-Fe2O3) sustituidas por gallio-titanio-cobalto y las nanopartículas ε-Fe2O3.
- Irradiación con láser pulsado de luz visible y láser pulsado de terahertz (THz).
- Demostración teórica mediante el cálculo estocástico de Landau-Lifshitz-Gilbert.
Principales resultados:
- Inversión de la magnetización inducida por irradiación láser de luz visible en películas GTC-ε-Fe2O3, cambiando el signo del efecto Faraday.
- La irradiación de luz pulsada THz en películas ε-Fe2O3 dio lugar a una rotación ultra rápida de Faraday dentro de los 400 fs.
- Los cálculos estocásticos de Landau-Lifshitz-Gilbert validaron la dinámica magnetoóptica ultrarrápida observada.
Conclusiones:
- Los nanomateriales magnéticos de óxido de hierro ε demuestran propiedades magnéticas sensibles a la luz.
- Estos materiales son prometedores para aplicaciones en medios de memoria magnética de alta densidad y dispositivos de circuitos magnéticos de alta velocidad.
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