Regensburg 2000 – wissenschaftliches Programm
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AM: Magnetismus
AM 13: Postersitzung: Dünne Schichten (1–22), Magnetowiderstand (23–40), Phasenübergänge (41–55), Mikromagnetismus (56–68), Spektroskopie (69–77), Nanokristalline Materialien (78–82), Anisotropie (83–86), Schmelzen (87–90), Weitere Bereiche (91–100)
AM 13.69: Poster
Dienstag, 28. März 2000, 16:00–20:00, A
Halfmetallic ferromagnetic behaviour of Heusler Alloys — •Franz Fangmeyer, Stefan Plogmann, Thorsten Schlathölter, Jürgen Braun, and Manfred Neumann — Fachbereich Physik, Universität Osnabrück, Barbarastraße 7, 49069 Osnabrück
Mn-based (X2MnZ) Heusler alloys (HA) are of great interest because of their HMF (half metallic ferromagnet) behaviour. The electronic and magnetic properties of different HA (X=Fe, Co, Ni, Pd; Z=Al, Si, Ga, In, Sn, Sb) were investigated by spectroscopic methods. With XPS (X-ray photoemission spectroscopy) we observed a magnetic splitting of the Mn 2p states which is proportional to the local magnetic moment at the Mn atom sites [1,2]. The partial density of states of the Mn 3d and the X 3d electrons were measured by XES (X-ray emission spectroscopy) and compared with the valence band measured by XPS. Investigations by SXE (soft X-ray emission) and XAS (X-ray absorption spectra) with circular polarized light were performed at the beamline ID12B at the ESRF, Grenoble, and show strong magnetic circular dichroism. From the XAS-MCD measurements, the spin and orbital moments, were deduced for NiMnSb and Ni2MnSb. The SXE-MCD measurements on NiMnSb show clear dichroism effects. Ab initio calculations were carried out and compared with experimental results.
This work was carried out in collaboration with the group of E. Z. Kurmaev, Institute of Metal Physics, Jekaterinburg, Russia, and the group of J. Nordgren, Physics Department, University of Uppsala, Sweden.
[1] Y. Yarmoshenko et al., Eur. Phys. J. B 2, 1-3 (1998)
[2] S. Plogmann et al., Phys. Rev. B, 60 (9), 6428, (1999)