Berlin 2005 – wissenschaftliches Programm
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MA: Magnetismus
MA 5: Spinstrukturen und magnetische Phasenüberg
änge
MA 5.6: Vortrag
Freitag, 4. März 2005, 11:45–12:00, TU EMH225
Angular dependent absorption spectroscopy of a de-twinned DyBaCo2O5.5 single crystal — •Myrsini Lafkioti1, Stefan Gold1, Eberhard Goering1, Gisela Schütz1, Joachim Deisenhofer2, and Peter Lemmens3 — 1Max-Planck-Institut für Metallforschung, 70569 Stuttgart — 2Lst. für Eperimentalphysik V, Uni-Augsburg, 86159 Augsburg — 3Inst. fuer Halbleiterphysik und Optik, TU Braunschweig, 38106 Braunschweig
The Perovskite DyBaCo2O5.5 exhibits a very rich phase diagram including two different paramagnetic, a ferromagnetic, and an antiferromagentic phase as a function of temperature[1]. In addition to these unusual properties, the system exhibits a very pronounced and strong magnetocrystalline anisotropy, with the easy axis along the crystallographic a-axis[2]. We will show detailed angular and temperature dependent X-ray magnetic circular dichroism and nonmagnetic linear polarized absorption spectroscopy results at the Co L2,3 and O K edges, performed on a de-twinned single crystal. A clear and quantitative correspondence between the microscopic and macroscopic magnetic behavior has been found. O K edge spectra reveal angular dependent variations, which give insight to the orbital character of the unoccupied states. Our results provide detailed information about the microscopic physics behind the observed unusual and also technical very promising properties. [1] A. Maignan et al., Journal of Solid State Chemistry 142, 247 (1999). [2] A. A. Taskin et al., Phys.Rev.Lett. 90, 227201-1 (2003).