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Los cristales coloidales 3D de magnetita se formaron en el sistema solar temprano hace 4.600 millones de años
Jun Nozawa1, Katsuo Tsukamoto, Willem van Enckevort
1Department of Earth and Planetary Materials Science, Graduate School of Science, Tohoku University, 6-3 Aramaki Aza-Aoba, Sendai 980-8578, Japan.
Journal of the American Chemical Society
|May 14, 2011
Resumen
Se descubrieron antiguos cristales coloidales de nanocristalitos de magnetita en un meteorito. Su morfología de partículas única y su estructura de dominio magnético permitieron la formación, desafiando los principios de síntesis previos para los materiales ferromagnéticos.
Área de la Ciencia:
- La geoquímica es la geoquímica.
- Ciencia de los materiales Ciencia de los materiales.
- Nanotecnología La nanotecnología es la nanotecnología.
Sus antecedentes:
- Los cristales coloidales tridimensionales suelen ser difíciles de sintetizar utilizando partículas ferromagnéticas debido a las fuertes interacciones magnéticas.
- La magnetita (Fe3O4) es un material ferromagnético común.
- Los cristales coloidales naturales como los ópalos son significativamente más jóvenes que la edad del sistema solar.
Objetivo del estudio:
- Para investigar la formación y estructura de antiguos cristales coloidales encontrados en el meteorito del lago Tagish.
- Comprender el papel de la morfología de partículas y las propiedades magnéticas en el autoensamblaje de nanocristallitos ferromagnéticos.
Principales métodos:
- Análisis de muestras de meteoritos que contienen cristales coloidales.
- Caracterización del tamaño, la morfología y la estructura de embalaje de la nanocristallita de magnetita.
- Hipótesis de estructuras de dominio magnético basadas en la formación de cristales observados.
Principales resultados:
- Descubrimiento de cristales coloidales 3D compuestos de nanocristallitos de magneto de tamaño uniforme (cientos de nanómetros) dentro del meteorito del lago Tagish.
- Estos cristales tienen aproximadamente 4.600 millones de años de antigüedad, y son anteriores a los cristales coloidales naturales terrestres.
- El tamaño de las partículas de magnetita dicta la morfología individual, lo que influye en la estructura general de embalaje de cristales coloidales.
Conclusiones:
- La formación de estos antiguos cristales coloidales ferromagnéticos desafía el principio de que las fuertes interacciones magnéticas impiden su síntesis.
- Una hipotética estructura de dominio magnético de flujo cerrado en cada partícula de magnetita probablemente mitiga las fuerzas magnéticas entre las partículas, permitiendo el autoensamblaje.
- Los hallazgos ofrecen información sobre la autoorganización de los nanomateriales magnéticos en las primeras condiciones del sistema solar.
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