FePt icosahedra with magnetic cores and catalytic shells

Wang, Rongming y Dmitrieva, Olga y Farle, Michael y Dumpich, Güntner y Acet, Mehmet y Mejía Rosales, Sergio y Pérez Tijerina, Eduardo y Yacamán, Miguel José y Kisielowski, Christian (2009) FePt icosahedra with magnetic cores and catalytic shells. Journal of physical chemistry C, 113. pp. 4395-4400. ISSN 1256-1260

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Resumen

Surprisingly oxidation resistant icosahedral FePt nanoparticles showing hard-magnetic properties have been fabricated by an inert-gas condensation method with in-flight annealing. High-resolution transmission electron microscopy (HRTEM) images with sub-Angstrom resolution of the nanoparticle have been obtained with focal series reconstruction, revealing noncrystalline nature of the nanoparticle. Digital dark-field method combined with structure reconstruction as well as HRTEM simulations reveal that these nanoparticles have icosahedral structure with shell periodicity. Localized lattice relaxations have been studied by extracting the position of individual atomic columns with a precision of about (0.002 nm. The lattice spacings of (111) planes from the surface region to the center of the icosahedra are found to decrease exponentially with shell numbers. Computational studies and energy-filtered transmission electron microscopy analyses suggest that a Pt-enriched surface layer is energetically favored and that site-specific vacancies are formed at the edges of facettes, which was experimentally observed. The presence of the Pt-enriched shell around an Fe/Pt core explains the environmental stability of the magnetic icosahedra and strongly reduces the exchange coupling between neighboring particles, thereby possibly providing the highest packing density for future magnetic storage media based on FePt nanoparticles.

Tipo de elemento: Article
Materias: Q Ciencia > Q Ciencias en General
Q Ciencia > QC Física
Divisiones: Ciencias Físico Matemáticas
Usuario depositante: Dr. Sergio J. Mejia Rosales
Creadores:
CreadorEmailORCID
Wang, RongmingNO ESPECIFICADONO ESPECIFICADO
Dmitrieva, OlgaNO ESPECIFICADONO ESPECIFICADO
Farle, MichaelNO ESPECIFICADONO ESPECIFICADO
Dumpich, GüntnerNO ESPECIFICADONO ESPECIFICADO
Acet, MehmetNO ESPECIFICADONO ESPECIFICADO
Mejía Rosales, SergioNO ESPECIFICADONO ESPECIFICADO
Pérez Tijerina, Eduardoeduardo.pereztj@uanl.edu.mxNO ESPECIFICADO
Yacamán, Miguel JoséNO ESPECIFICADONO ESPECIFICADO
Kisielowski, ChristianNO ESPECIFICADONO ESPECIFICADO
Fecha del depósito: 08 Feb 2016 21:38
Última modificación: 08 Feb 2016 21:38
URI: http://eprints.uanl.mx/id/eprint/8950

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