Dresden 2009 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 35: Spin-Dynamics / Spin-Torque IV
MA 35.12: Vortrag
Donnerstag, 26. März 2009, 18:15–18:30, HSZ 04
Thermally Induced Magnetization Reversal of Fe/W(110) Nanoislands Investigated by SP-STM — •Stefan Krause1, Gabriela Herzog1, Luis Berbil-Bautista2, Matthias Bode3, and Roland Wiesendanger1 — 1Institute of Applied Physics, University of Hamburg, Germany — 2Materials Science Division, Lawrence Berkeley National Laboratory, USA — 3Center for Nanoscale Materials, Argonne National Laboratory, USA
Spin-polarized scanning tunneling microscopy (SP-STM) is a well-established tool to investigate not only static but also dynamic magnetic properties of surfaces at lateral resolution down to the atomic scale [1]. Our variable-temperature STM is suitable to investigate the thermal switching behavior of single atomic-scale Fe/W(110) nanoislands over a temperature range between 30 K and 300 K.
Both the attempt frequency as well as the effective activation energy barrier of individual nanoislands can be determined from the Arrhenius-like switching behavior as a function of temperature. An analysis of the data reveals that magnetization reversal takes place via the nucleation and propagation of a domain wall. Furthermore, the attempt frequency is found to vary with island size and shape.
The results will be discussed in terms of domain wall nucleation and diffusion. For atoms at the center and the rim of a nanoisland the exchange stiffness and anisotropy energy contributions are to be quantified and compared to the results of earlier studies on the Fe/W(110) monolayer system.
[1] M. Bode et al., Phys. Rev. Lett. 92, 067201 (2004).