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2005 | 3 | 2 | 209-220
Tytuł artykułu

Classical simulations of magnetic structures for chromium clusters: Size effects

Treść / Zawartość
Warianty tytułu
Języki publikacji
EN
Abstrakty
EN
Classical (Heisenberg) simulations show that the total magnetization of the lowest-energy states of clusters made of antiferromagnetically coupled chromium atoms is planar, rather than collinear, depending on the arrangement of the atoms. Although the model Hamiltonian is not restrictive, many cluster configurations of various numbers of atoms do not use all three directions for the spins. This result confirms the conclusion drawn from the local-spin DFT calculation by Kohl and Bertsch that clusters of N≤13 have non-collinear magnetic moments. The present simulations show non-collinear spin ordering also for bigger clusters, designed to be as spherical as possible following the bcc arrangement, when atoms interact both with the nearest and next-nearest neighbours. Depending on the signs of the coupling constants frustration appears. The advantage of the discrete model, despite the simplicity, is that very large clusters and magnetization at finite temperatures can be studied. This model predicts that clusters with specific numbers of atoms interacting only with the nearest neighbours have collinear spins as in the bulk. We also apply the model to simulate the destruction of the anti-ferromagnetic ordering by thermal fluctuations. This model shows no unique magnetization of mixed Fe 0.33 Cr 0.67, which is consistent with experimental observations.
Wydawca

Czasopismo
Rocznik
Tom
3
Numer
2
Strony
209-220
Opis fizyczny
Daty
wydano
2005-06-01
online
2005-06-01
Twórcy
autor
  • Department of Atomic Physics, University of Sofia, 5 James Bourchier Blvd., 1126, Sofia, Bulgaria, anap@phys.uni-sofia.bg
Bibliografia
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Typ dokumentu
Bibliografia
Identyfikatory
Identyfikator YADDA
bwmeta1.element.-psjd-doi-10_2478_BF02475588
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