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O: Oberflächenphysik

O 13: Magnetismus

O 13.4: Talk

Friday, March 4, 2005, 16:30–16:45, TU EB107

Complex magnetism of small 3d transition metal clusters on Ni and Cu surfaces — •Phivos Mavropoulos, Samir Lounis, Rudolf Zeller, Stefan Blügel, and Peter H. Dederichs — IFF, Forschungszentrum Jülich, D-52425 Jülich, Germany

We present ab-initio calculations of magnetic clusters on non-magnetic or magnetic substrates. Firstly, we study small clusters (1-9 atoms) of Fe, Cu, and Ni on Ni and Cu surfaces. Emphasis is given on the dependence of the spin moments on cluster shape and size. For Fe we derive a quantitative rule connecting the moment of each Fe atom linearly to its coordination number. Thus the moment of an arbitrary cluster can be readily found if the positions of the atoms are known. For Co clusters the rule holds to a lesser extent, and much less so for Ni clusters.

Secondly, we focus on small magnetic Mn and Cr clusters, where a competition between ferro– and antiferromagnetic interactions can lead to noncollinear spin structures. The size and orientation of the local moments and the stabilization of noncollinear magnetic state are investigated.

Work supported by the DFG Schwerpunktsprogramm “Clusters in contact with Surfaces” (SPP 1153).