Berlin 2012 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 36: Magnetic Heusler Compounds II
MA 36.4: Vortrag
Donnerstag, 29. März 2012, 10:45–11:00, H 1012
Significant Spin Polarization of Co2MnGa measured by multichannel spinresolved UPS — •Michaela Kolbe, Gerd Schönhense, Mathias Kläui, and Martin Jourdan — Institut für Physik, Universität Mainz, Staudinger Weg 7, 55128 Mainz
The spin dependent valence band structure of the Heusler compound Co2MnGa was investigated using spin resolved ultraviolet photoelectron spectroscopy (SRUPS) in a new multichannel detection mode [1]. Special care was taken concerning the preservation of a clean and crystallographically undistorted sample surface by the combination of UHV- thin film preparation and in-situ spectroscopy. Referring to the extreme surface sensitive detection method, Co2MnGa is a relatively inert Heusler material. Nevertheless, the in-situ investigation proved to be advantageous compared to our previous vacuum-suitcase transport method [2] resulting in a further reduced oxidation.
A high spin polarization of 55% at the Fermi energy was observed which decreases at higher binding energies and shows a sign change at 0.7eV. This experimental result is in good agreement with theoretical predictions for the bulk density of states of this Heusler compound [3]. The possible influence of surface states on the obtained experimental results is discussed.
Financial support by the Stiftung Rheinland-Pfalz für Innovation (project 886) and the DFG (Scho341/9-1, Jo404/4-1) is acknowledged.
[1] M. Kolbe et al., Phys. Rev. Lett. 107, 207601 (2011) [2] M. Hahn et al., Appl. Phys. Lett. 98, 232503 (2011) [3] I. Galanakis et al., J. Phys. D: Appl. Phys. 39, 765 (2006)