Berlin 2005 – wissenschaftliches Programm

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MA: Magnetismus

MA 28: Magnetische Partikel/Cluster I

MA 28.3: Vortrag

Dienstag, 8. März 2005, 15:45–16:00, TU H1028

Temperature Dependence of Magnetic Properties of Small Ferromagnetic Clusters — •Svetlana Polesya¹, Sven Bornemann¹, Jan Minár¹, Hubert Ebert¹, and Ondrej Šipr² — ¹Dept. Chemie und Biochemie, Universität München, Butenandtstr. 5-13, D-81377 München, Germany — ²Institute of Physics Acad. of Sci. of the Czech Republic, Cukrovarnicka 10, Praha 6 162 53, Czech Republic

The temperature dependence of the magnetic properties of small ferromagnetic clusters has been studied within the extended classical Heisenberg model using Monte-Carlo simulations. The exchange coupling constants were obtained from ab   initio spin-polarized KKR calculations of the electronic structure. Results of calculations for Co clusters both unsupported and deposited on Pt(111) surface will be presented. In particular the influence of the spin-orbit induced anisotropy on their thermodynamic properties will be discussed. The peculiarities of the cluster electronic structure lead to a nonmonotonical size dependent Curie temperature for small Fe, Co and FePt clusters. The use of exchange coupling constants taken from bulk calculations on the other hand results in a monotonous increase of the Curie temperature.