Dipolar magnetism in ordered and disordered low-dimensional nanoparticle assemblies
Varón Izquierdo, Miriam (Institut Català de Nanociència i Nanotecnologia)
Beleggia, Marco (Danmarks tekniske universitet. Center for Elektronnanoskopi)
Kasama, Takeshi (Danmarks tekniske universitet. Center for Elektronnanoskopi)
Harrison, R. J. (University of Cambridge. Department of Earth Sciences)
Dunin-Borkowski, Rafal E. (Ernst Ruska-Centrum für Mikroskopie und Spektroskopie mit Elektronen)
Puntes, Víctor (Institut Català de Nanociència i Nanotecnologia)
Frandsen, Cathrine (Danmarks tekniske universitet. Institut for Fysik)

Date:	2013
Abstract:	Magnetostatic (dipolar) interactions between nanoparticles promise to open new ways to design nanocrystalline magnetic materials and devices if the collective magnetic properties can be controlled at the nanoparticle level. Magnetic dipolar interactions are sufficiently strong to sustain magnetic order at ambient temperature in assemblies of closely-spaced nanoparticles with magnetic moments of ≥ 100â. . . μ B. Here we use electron holography with sub-particle resolution to reveal the correlation between particle arrangement and magnetic order in self-assembled 1D and quasi-2D arrangements of 15â. . . nm cobalt nanoparticles. In the initial states, we observe dipolar ferromagnetism, antiferromagnetism and local flux closure, depending on the particle arrangement. Surprisingly, after magnetic saturation, measurements and numerical simulations show that overall ferromagnetic order exists in the present nanoparticle assemblies even when their arrangement is completely disordered. Such direct quantification of the correlation between topological and magnetic order is essential for the technological exploitation of magnetic quasi-2D nanoparticle assemblies.
Grants:	Ministerio de Ciencia e Innovación BES-2007-17164
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Magnetic devices ; Magnetic properties and materials ; Nanoparticles ; Two-dimensional materials
Published in:	Scientific reports, Vol. 3 (2013) , art. 1234, ISSN 2045-2322

DOI: 10.1038/srep01234
PMID: 23390584

5 p, 3.0 MB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Catalan Institute of Nanoscience and Nanotechnology (ICN2)
Articles > Research articles
Articles > Published articles