Dresden 2017 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 65: Poster 2
MA 65.20: Poster
Freitag, 24. März 2017, 09:30–13:00, P2-OG1
Microscopic View of Magnetic Anisotropy in Permalloy — •Debora C M Rodrigues1,2, Angela B Klautau2, Alexander Edström1, Jan Rusz1, Lars Nordström1, Manuel Pereiro1, Björgvin Hjörvarsson1, and Olle Eriksson1 — 1Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden — 2Faculty of Physics, Federal University of Pará, Belém, Brazil
Permalloy (Py) is the common name for Fe-Ni alloys, with concentration of 80 % Ni and 20 % Fe, and known due to its vanishingly low magnetic anisotropy energy (MAE) and low damping parameter. Py may be viewed as a huge ensemble of interconnected clusters of Fe-Ni atoms distributed on an fcc lattice. Therefore, by means of relativistic first principles calculations, we investigated the microscopic origin of the vanishingly low magnetic anisotropy of Py. The study was focus on evaluating the orbital moment anisotropy of clusters composed by Fe and Ni, with different configurations, embedded in an effective medium of Py. The MAE is obtained by relating the orbital moment anisotropy and local magnetic anisotropy. As result, we found that the local MAE can be much larger than that of the Py bulk sample, and at least the same order order of magnitude than of Fe or Ni bulk. We discuss these results in terms of local symmetries of the alloy and conclude that the vanishingly small MAE would be the result of a proper configurational average.