D Serantes et al 2009 J. Phys. D: Appl. Phys. 42 215003 doi:10.1088/0022-3727/42/21/215003
D Serantes1, D Baldomir1, M Pereiro1, B Hernando2, V M Prida2, J L Sánchez Llamazares2, A Zhukov3, M Ilyn3 and J González3
Show affiliationsThe magnetic order in parallel-aligned one-dimensional (1D) chains of magnetic nanoparticles is studied using a Monte Carlo technique. If the easy anisotropy axes are collinear along the chains a macroscopic mean-field approach indicates antiferromagnetic (AFM) order even when no interparticle interactions are taken into account, which evidences that a mean-field treatment is inadequate for the study of the magnetic order in these highly anisotropic systems. From the direct microscopic analysis of the evolution of the magnetic moments, we observe spontaneous intra-chain ferromagnetic (FM)-type and inter-chain AFM-type ordering at low temperatures (although not completely regular) for the easy-axes collinear case, whereas a random distribution of the anisotropy axes leads to a sort of intra-chain AFM arrangement with no inter-chain regular order. When the magnetic anisotropy is neglected a perfectly regular intra-chain FM-like order is attained. Therefore it is shown that the magnetic anisotropy, and particularly the spatial distribution of the easy axes, is a key parameter governing the magnetic ordering type of 1D-nanoparticle chains.
75.75.+a Magnetic properties of nanostructures
75.40.Mg Numerical simulation studies
Issue 21 (7 November 2009)
Received 29 July 2009, in final form 1 September 2009
Published 13 October 2009
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