Dresden 2009 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 17: Magnetic Thin Films I
MA 17.5: Vortrag
Mittwoch, 25. März 2009, 11:15–11:30, HSZ 04
Trends in exchange interactions for bcc Fe/TaW(001) — •Martin Ondráček1, Josef Kudrnovský1, Olivier Bengone2, Ilja Turek3,4, and František Máca1 — 1Institute of Physics ASCR, Prague — 2University of Strasbourg, IPCM, Strasbourg — 3Institute of Physics of Materials ASCR, Brno — 4Department of Condensed Matter Physics, Charles University, Prague
A recent study of Ferriani et al. [1] investigated the possibility of tuning the magnetic order of the Fe monolayer on the disordered bcc-Ta(x)W(1-x)[001] surface. We will further extend this study by constructing the effective two-dimensional Heisenberg Hamiltonian, which describes exchange interactions in the iron monolayer in detail. We will investigate the behavior of exchange integrals as a function of the composition of the alloy substrate, but also as a function of distance (damping due to disorder) and the dependence on the crystallographic directions in the overlayer. The calculated exchange integrals allow us to estimate the spin stiffness and the corresponding critical temperatures. We also wish to investigate the crossover between the ferromagnetic and antiferromagnetic state from the point of view of the stability of the Heisenberg Hamiltonian with respect to magnon excitations. The present study will help us to deeper understand the character of magnetic phase transition of the Fe overlayer due to disorder in the alloy substrate.
[1] P. Ferriani, I. Turek, S. Heinze, G. Bihlmayer, and S. Blügel, Phys. Rev. Lett. 99 (2007) 187203.