The Kondo effect in ferromagnetic atomic contacts
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Título: | The Kondo effect in ferromagnetic atomic contacts |
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Autor/es: | Calvo, M. Reyes | Fernández-Rossier, Joaquín | Palacios Burgos, Juan José | Jacob, David | Natelson, Douglas | Untiedt, Carlos |
Grupo/s de investigación o GITE: | Grupo de Nanofísica |
Centro, Departamento o Servicio: | Universidad de Alicante. Departamento de Fisica Aplicada | Rutgers University. Department of Physics and Astronomy | Rice University. Department of Physics and Astronomy |
Palabras clave: | Electronic transport | Magnetism | Nanocontacts | Kondo |
Área/s de conocimiento: | Física Aplicada |
Fecha de publicación: | 30-abr-2009 |
Editor: | Macmillan Publishers |
Cita bibliográfica: | CALVO, M. Reyes, et al. “The Kondo effect in ferromagnetic atomic contacts”. Nature. Vol. 458 (30 Apr. 2009). ISSN 0028-0836, pp. 1150-1154 |
Resumen: | Iron, cobalt and nickel are archetypal ferromagnetic metals. In bulk, electronic conduction in these materials takes place mainly through the s and p electrons, whereas the magnetic moments are mostly in the narrow d-electron bands, where they tend to align. This general picture may change at the nanoscale because electrons at the surfaces of materials experience interactions that differ from those in the bulk. Here we show direct evidence for such changes: electronic transport in atomic-scale contacts of pure ferromagnets (iron, cobalt and nickel), despite their strong bulk ferromagnetism, unexpectedly reveal Kondo physics, that is, the screening of local magnetic moments by the conduction electrons below a characteristic temperature1. The Kondo effect creates a sharp resonance at the Fermi energy, affecting the electrical properties of the system; this appears as a Fano–Kondo resonance2 in the conductance characteristics as observed in other artificial nanostructures3–11. The study of hundreds of contacts shows material-dependent lognormal distributions of the resonance width that arise naturally from Kondo theory12. These resonances broaden and disappear with increasing temperature, also as in standard Kondo systems4–7. Our observations, supported by calculations, imply that coordination changes can significantly modify magnetism at the nanoscale. Therefore, in addition to standard micromagnetic physics, strong electronic correlations along with atomic-scale geometry need to be considered when investigating the magnetic properties of magnetic nanostructures. |
Patrocinador/es: | This work was partly supported by the European Union through MolSpinQIP and Spanish MEC (grants MAT2007-65487, 31099-E and CONSOLIDER CSD2007-0010). D.J. acknowledges funding by the US National Science Foundation (NSF) under grant DMR-0528969. D.N. acknowledges the support of NSF grant DMR-0347253, the David and Lucille Packard Foundation and the W. M. Keck Program in Quantum Materials. |
URI: | http://hdl.handle.net/10045/17533 |
ISSN: | 0028-0836 (Print) | 1476-4687 (Online) |
DOI: | 10.1038/nature07878 |
Idioma: | eng |
Tipo: | info:eu-repo/semantics/article |
Revisión científica: | si |
Versión del editor: | http://dx.doi.org/10.1038/nature07878 |
Aparece en las colecciones: | Investigaciones financiadas por la UE INV - Grupo de Nanofísica - Artículos de Revistas |
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2009Nature.pdf | Versión final (acceso restringido) | 539,62 kB | Adobe PDF | Abrir Solicitar una copia |
nature07878-s1.pdf | Supplementary Information. Versión final (acceso restringido) | 291,55 kB | Adobe PDF | Abrir Solicitar una copia |
2009Nature_Authors_Version.pdf | Versión revisada (acceso abierto) | 318,81 kB | Adobe PDF | Abrir Vista previa |
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