Collective states of interacting ferromagnetic nanoparticles

被引：159
作者：
Petracic, O
Chen, X
Bedanta, S
Kleemann, W [1 ]
Sahoo, S
Cardoso, S
Freitas, PP
机构：
[1] Univ Duisburg Gesamthsch, D-47048 Duisburg, Germany
[2] Univ Nebraska, Dept Phys & Astron, Lincoln, NE 68588 USA
[3] INESC, P-1000 Lisbon, Portugal
来源：
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS | 2006年 / 300卷 / 01期
关键词：
magnetic nanoparticles; dipolar interaction; superspin glass; superferromagnetism;
D O I：
10.1016/j.jmmm.2005.10.061
中图分类号：
T [工业技术];
学科分类号：
08 ;
摘要：
Discontinuous magnetic multilayers [CoFe/Al2O3] are studied by use of magnetometry, susceptometry and numeric simulations. Soft ferromagnetic Co80Fe20 nanoparticles are embedded in a diamagnetic insulating a-Al2O3 matrix and can be considered as homogeneously magnetized superspins exhibiting randomness of size (viz. moment), position and anisotropy. Lacking intra-particle core-surface ordering, generic freezing processes into collective states rather than individual particle blocking are encountered. With increasing particle density one observes first superspin glass and then superferromagnetic domain state behavior. The phase diagram resembles that of a dilute disordered ferromagnet. Criteria for the identification of the individual phases are given. (c) 2005 Elsevier B.V. All rights reserved.
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收藏
页码：192 / 197
页数：6
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