Document Detail


Collective behaviour in two-dimensional cobalt nanoparticle assemblies observed by magnetic force microscopy.
MedLine Citation:
PMID:  15048109     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The use of magnetic nanoparticles in the development of ultra-high-density recording media is the subject of intense research. Much of the attention of this research is devoted to the stability of magnetic moments, often neglecting the influence of dipolar interactions. Here, we explore the magnetic microstructure of different assemblies of monodisperse cobalt single-domain nanoparticles by magnetic force microscopy and magnetometric measurements. We observe that when the density of particles per unit area is higher than a determined threshold, the two-dimensional self-assemblies behave as a continuous ferromagnetic thin film. Correlated areas (similar to domains) of parallel magnetization roughly ten particles in diameter appear. As this magnetic percolation is mediated by dipolar interactions, the magnetic microstructure, its distribution and stability, is strongly dependent on the topological distribution of the dipoles. Thus, the magnetic structures of three-dimensional assemblies are magnetically soft, and an evolution of the magnetic microstructure is observed with consecutive scans of the microscope tip.
Authors:
Victor F Puntes; Pau Gorostiza; Deborah M Aruguete; Neus G Bastus; A Paul Alivisatos
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.     Date:  2004-03-28
Journal Detail:
Title:  Nature materials     Volume:  3     ISSN:  1476-1122     ISO Abbreviation:  Nat Mater     Publication Date:  2004 Apr 
Date Detail:
Created Date:  2004-04-01     Completed Date:  2004-05-25     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  101155473     Medline TA:  Nat Mater     Country:  England    
Other Details:
Languages:  eng     Pagination:  263-8     Citation Subset:  IM    
Affiliation:
Physics Department, University of Barcelona, 08028 Barcelona, Spain. vfpuentes@ffn.ub.es
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MeSH Terms
Descriptor/Qualifier:
Anisotropy
Cobalt / chemistry*
Image Processing, Computer-Assisted
Magnetics*
Microscopy, Atomic Force / instrumentation*,  methods*
Nanotechnology / methods*
Software
Grant Support
ID/Acronym/Agency:
1 R01 RR-14891-01/RR/NCRR NIH HHS
Chemical
Reg. No./Substance:
7440-48-4/Cobalt

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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