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Seminario
"NMR of Co in Ferrites"

Relatore: Dr. Martin Pieper- Graz University
Note: Orario puntuale

Nuova Sala Riunioni
11 Maggio 2011 ore 12.00

Abstract
Cobalt doped ferrites with spinel and hexaferrite structure have been the working horses of the permanent magnet industry since more than 50 years. While the basic mechanism of the enhancement of magnetic anisotropy, the orbital moment of the Co ion, was identified early on the models to describe the magnetic anisotropy remained rather crude. This is on one hand due to the difficulty to calculate the elctronic structure in such a detail in a realistic model, and on the other hand due to a lack of experimental data on the local electronic structure. This talk will present preliminary results of our work on both aspects: Modern full potential density functional theory calculations provide an (almost) parameter free tool to calculate realistic band structures and from there the hyperfine fields as well as magnetic anisotropy energy. NMR of Co is a very sensitive tool to study the local electronic structure and the existance of unquenched orbital moments.