Berlin 2008 – scientific programme

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MA: Fachverband Magnetismus

MA 28: Magnetic Thin Films III

MA 28.2: Talk

Thursday, February 28, 2008, 14:45–15:00, H 1012

An ab-initio description of the magnetic shape anisotropy — •Sven Bornemann and Hubert Ebert — Department Chemie und Biochemie, LMU München, Germany

For magnetic transition metal systems with reduced dimensionality and low symmetry the shape anisotropy becomes a significant contribution to the magnetic anisotropy. In fact, it can reach the same order of magnitude as the spin-orbit induced anisotropy. So far, the shape anisotropy has been always treated as a classical interaction between magnetic dipoles while the spin-orbit anisotropy has been determined by relativistic band structure calculations. It is uncertain, however, whether such an inconsistent treatment of the two anisotropy contributions is still valid for low dimensional nano structures such as magnetic thin films, wires or clusters where the magnetic easy axis can depend strongly on the interplay between these two contributions.

As an alternative to the standard approach an ab-initio description of the shape anisotropy has been developed. This is achived by including the Breit interaction, which is the natural cause of the shape anisotropy, in the Dirac-equation set up within the framework of spin density functional theory. We have implemented this approach using the fully relativistic KKR band structure scheme. We will present the details of our implementation and show first results for the shape anisotropy of thin films in comparison with the classical treatment.