Berlin 2015 – scientific programme
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MA: Fachverband Magnetismus
MA 30: Magnetic Materials II
MA 30.5: Talk
Wednesday, March 18, 2015, 16:00–16:15, H 0112
Electron-electron interaction strength in ferromagnetic nickel determined by spin-polarized positron annihilation — •Hubert Ceeh1, Josef-Andreas Weber1, Michael Leitner1, Liviu Chioncel2, Dieter Vollhardt2, Diana Benea3, Peter Böni1, Hubert Ebert3, Jan Jan Minár3, and Christoph Hugenschmidt1 — 1Technische Universität München, Physik Department, Lehrstuhl E21, James-Franck-Straße, D-85748 Garching, Germany — 2Theoretical Physics III, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, D-86135 Augsburg, Germany — 3Chemistry Department, University Munich, Butenandstraße 5-13, D-81377 München, Germany
Spin resolved positron annihilation measurements using the angular correlation of annihilation radiation technique have been performed on ferromagnetic Ni. The analysis is based on a direct comparison of the experimentally obtained projections of the momentum density and state-of-the-art dynamic mean-field calculations. The experimental data were best described for a value of 2.0 eV for the on-site repulsion term U in the Hubbard model. We show that spin-polarized 2D-ACAR, where probe effects of the positron can be avoided, is a powerful tool to investigate the electronic structure of ferromagnetic systems.