Regensburg 2004 – wissenschaftliches Programm

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MA: Magnetismus

MA 13: Poster:Schichten(1-23),Spinabh.Trsp(24-41),Exch.Bias(42-56),Spindyn.(57-67),Mikromag.(68-76),Partikel(77-90),Spinelektr.(91-97),Elektr.Theo.(98-99),Mikromag+PhasÜ+Aniso.(100-105),Magn.Mat.(106-118),Messmethod.(119-121),Obflm.+Abbverf.(122-123)

MA 13.114: Poster

Dienstag, 9. März 2004, 15:00–19:00, Bereich A

Characterization of doped Heusler alloys: Co₂Cr_1−xFe_xAl — •S. Wurmehl¹, G. H. Fecher¹, H. C. Kandpal¹, K. Kroth¹, H.-J. Elmers¹, G. Schönhense¹, C. Felser¹, J. Morais², Y. Hwu³, and R. Klauser⁴ — ¹Johannes Gutenberg - Universität, D-55099 Mainz, Germany — ²Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre, Brazil — ³Academia Sinica, Taipei, 11529, Taiwan — ⁴National Synchrotron Radiation Research Center, Hsinchu, 30077, Taiwan

Doped Heusler alloys and compounds of the Co₂Cr_1−xFe_xAl with varying Cr to Fe ratio x were produced and experimentally investigated. Most of the samples showed pronounced disorder instead of the expected L2₁ structure. The sample surfaces exhibited a strong selective oxidation of chromium. The bulk samples were characterized by standard methods such as X-ray diffraction, SQUID magnetometry, and depth profiling. X-ray absorption was used together with XMCD to examine different oxidation stages in bulk and powder samples and to determine element specific magnetic moments. Surface sensitive methods, like low energy ion scattering, photoemission, PEEM, and scanning XPS microscopy, were used to examine the oxidation process. The nature of the selective oxidation of chromium in these compounds will be discussed on hand of the experimental findings.