Spin waves cause non-linear friction

In: EPL (Europhysics Letters), Jg. 95 (2011) ; Nr. 1, S. 17010
ISSN: 1286-4854, 0295-5075
Zeitschriftenaufsatz / Fach: Physik
Fakultät für Physik » Theoretische Physik
Energy dissipation is studied for a hard magnetic tip that scans a soft magnetic substrate. The dynamics of the atomic moments are simulated by solving the Landau-Lifshitz-Gilbert (LLG) equation numerically. The local energy currents are analysed for the case of a Heisenberg spin chain taken as substrate. This leads to an explanation for the velocity dependence of the friction force: The non-linear contribution for high velocities can be attributed to a spin wave front pushed by the tip along the substrate.