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Published on: September 13, 2019
Relajación magnética lenta en un hierro de alto espín (II) complejo
Danna E Freedman1, W Hill Harman, T David Harris
1Department of Chemistry and Howard Hughes Medical Institute, University of California, Berkeley, California 94720, USA.
Journal of the American Chemical Society
|January 9, 2010
Resumen
Los investigadores descubrieron el primer complejo de hierro mononuclear exhibiendo un comportamiento magnético de una sola molécula. Este complejo muestra una lenta relajación magnética, crucial para el desarrollo de materiales magnéticos moleculares.
Área de la Ciencia:
- Química Inorgánica La Química Inorgánica es la química inorgánica.
- Ciencia de los materiales Ciencia de los materiales.
- La física cuántica es la física cuántica.
Sus antecedentes:
- Los imanes de molécula única (SMM) son cruciales para el desarrollo de almacenamiento de datos de alta densidad y computación cuántica.
- Los complejos de metales de transición mononucleares se investigan activamente para las propiedades de SMM.
- Comprender los mecanismos de relajación magnética es clave para diseñar SMM eficientes.
Objetivo del estudio:
- Para reportar el primer complejo de metal de transición mononuclear que exhibe un comportamiento magnético de una sola molécula.
- Investigar las propiedades magnéticas y la dinámica de relajación de un complejo de hierro de alto espín.
- Para aclarar el papel del túnel cuántico y los campos aplicados en la relajación magnética.
Principales métodos:
- Síntesis y caracterización del complejo trigonal piramidal hierro (II) complejo (tpa (Mes) Fe) ().
- Mediciones de susceptibilidad magnética y magnetización de CC para determinar la anisotropía magnética.
- Mediciones de susceptibilidad magnética de CA para estudiar la dinámica de relajación magnética bajo diferentes campos de CC.
Principales resultados:
- El complejo exhibe una lenta relajación magnética, característica del comportamiento del imán de una sola molécula.
- Se determinó una fuerte anisotropía magnética uniaxial (D = -39.6 cm(-1)) para el estado fundamental S = 2.
- El túnel cuántico de la magnetización se observó a cero aplicado campo de CC.
- La aplicación de un campo de 1500 Oe DC inició una lenta relajación magnética, con un mecanismo activado térmicamente a altas temperaturas y un túnel independiente de la temperatura a bajas temperaturas.
- El tiempo de relajación magnética mostró un máximo de aproximadamente 1500 Oe.
Conclusiones:
- [(tpa(Mes))Fe](-) es el primer complejo de metal de transición mononuclear que demuestra propiedades magnéticas de una sola molécula.
- La relajación magnética observada se rige por una combinación de procesos activados térmicamente y túnel cuántico, influenciado por campos de CC aplicados.
- Este hallazgo abre nuevas vías para el diseño de materiales magnéticos moleculares con propiedades sintonizables.
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