Dresden 2006 – wissenschaftliches Programm
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MA: Magnetismus
MA 20: Poster: Films(1-36) Transp(37-56) Ex.Bias(57-67) Spindyn(68-80) Micromag(81-95) Particle(96-109) Imag.+Surface(110-113) Spinelectr(114-122) Theory+Micromag(123-131) Spinstr+Aniso(132-142) MagMat(143-156) Meas(157,158) MolMag+Kondo(159-162) Postdead(163-)
MA 20.22: Poster
Dienstag, 28. März 2006, 15:15–19:15, P1
Circular magnetic dichroism in X-ray absorption of epitaxial Co2Cr1−xFexAl andCo2FeSi Heusler alloy films — •M. Kallmayer1, A. Gloskovskii2, K. Kroth2, U. Stumm2, A. Conca1, H. Schneider1, G. Jakob1, M. Jourdan1, and H.J. Elmers1 — 1Johannes Gutenberg-Universität Mainz, Institut für Physik, Staudingerweg 7, D-55099 Mainz — 2Johannes Gutenberg-Universität Mainz, Institut für Anorganische Chemie und Analytische Chemie, Staudingerweg 9, D-55099 Mainz
Co2Cr1−xFexAl and Co2FeSi are potential candidates for providing a high spin-polarization at the Fermi surface. Element-specific magnetic properties as determined by X-ray magnetic circular dichroism (XMCD) provide a key test for band structure calculations. XMCD spectra were determined by measuring the total electron and fluorescence yield. Epitaxial Co2Cr1−xFexAl(100) films grown on MgO(100) by sputter deposition provide a high degree of local atomic order (B2 structure) that coincides with the occurrence of a magnetic dichroism at the Cr 2p edge which could not be observed for less ordered polycrystalline films. Epitaxial Co2FeSi(100) and Co2FeSi(110) films grown on MgO(100) and Al2O3(1120), respectively, reveal a comparatively high magnetic moment of 2.6 µB (Fe) and 1.2 µB (Co) per formula unit at room temperature in agreement with the mean magnetization measured by magnetometry. The fluorescence yield spectra at the Co 2p edge significantly depends on the crystallographic orientation of the epitaxial films. We discuss the dependence of the orbital to spin moment ratio on the magnetization direction with respect to the film normal.