Dresden 2006 – wissenschaftliches Programm
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MA: Magnetismus
MA 36: Magnetic Coupling Phenomena / Exchange-Bias
MA 36.7: Vortrag
Freitag, 31. März 2006, 12:15–12:30, HSZ 401
Temperature dependent effects of interlayer exchange coupling in rare earth trilayers — •M. Wietstruk, K.M. Döbrich, J.E. Prieto, O. Krupin, F. Heigl, G. Kaindl, and K. Starke — Freie Universität Berlin, Fachbereich Physik
We investigated the thickness and temperature dependence of the interlayer exchange coupling (IEC) in Tb/Y/Gd-Trilayers. Using wedge samples with Y-spacer layer thicknesses between 5 and 35Å, we recorded hysteresis loops by x-ray magneto-optical Kerr effect (XMOKE) at the Gd M5 edge. By scanning along the wedge, we could measure about 1.5 oscillation periods of the coupling strength on each sample.
In this all-rare-earth-metal system, we find that the phase of the oscillatory coupling shifts with temperature. In particular, for a fixed spacer layer thickness of 15Å, the coupling changes reversibly between ferromagnetic and antiferromagnetic, when changing the temperature between 20K and 120K.
We compare the experimental findings with simple model calculations in the quantum-well-state picture with free-electron reflectivities. Additionally, we present QWS calculations for this system using theoretical valence band dispersions of bulk Tb, Y, and Gd.