کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10710568 | 1024698 | 2005 | 5 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Thermodynamic properties of antiferromagnetic clusters
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
فیزیک و نجوم
فیزیک ماده چگال
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چکیده انگلیسی
The finite temperature magnetic properties of antiferromagnetic (AF) clusters are investigated in the framework of the Hubbard model at half-band filling. The ground- and excited-state electronic energies En, the corresponding wave functions |Ψnã, and the total spin Sn are calculated exactly by using a full many-body diagonalization method. A complete optimization and sampling of the topological structures of the cluster is performed. Representative results are presented for the specific heat C(T), magnetic susceptibility Ï(T), and spin correlation functions γij(T) between sites i and j of clusters having N=7 atoms. Low-temperature peaks in C(T) are observed and they are interpreted in terms of the spin-resolved excitation spectrum. Ï(T) shows a typical AF-like behavior of the form Ïâ1/(T+TN) from which the cluster “Néel'' temperature TN is derived. Finally, the effects of temperature-induced fluctuations of the cluster structure are discussed.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Magnetism and Magnetic Materials - Volume 294, Issue 2, July 2005, Pages e27-e31
Journal: Journal of Magnetism and Magnetic Materials - Volume 294, Issue 2, July 2005, Pages e27-e31
نویسندگان
F. López-UrÃas, G.M. Pastor,