Magnetic anisotropy: fundamentals and applications

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Date/Time:Thursday, 24 Oct 2013 - Saturday, 26 Oct 2013
Location:PHYSICS Hall Room 3
Channel:Condensed Matter Physics
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Vladimir Antropov Ames Lab

We will present some fundamental physics related results obtained in a course of work for applied magnetism projects at Ames Laboratory.

These results allowed us to explain unusual properties of materials and predict better magnets. We will concentrate on the physics of such mesoscopic property as magnetic anisotropy, which is important on all length scales ranging from a quantum to a classical description. Starting from very simple models of magnetic anisotropy in molecules and solids, we will discuss a screening of atomic spin orbital coupling in solids and how it affects anisotropy. Using a novel virial theorem for magnetic anisotropy as well as perturbation theory, we obtained some general statements about constituents of anisotropy and their spatial distribution. As an example, large two-ion anisotropy effects in itinerant magnets (currently assumed to be small) will be presented for the first time. If time allows, we will explain the microscopic origin of magnetic anisotropy in the popular systems CoPt/FePt, FeNi, MnBi, Fe-Li-N, R2Co17, and others.