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MA: Fachverband Magnetismus

MA 30: Spin-Dynamics / Spin-Torque III

MA 30.5: Vortrag

Donnerstag, 26. März 2009, 11:15–11:30, HSZ 04

Simulations of current-induced domain wall motion including temperature effects using the Landau-Lifshitz-Bloch equation — •Christine Schieback, Denise Hinzke, Mathias Kläui, Ulrich Rüdiger, Ulrich Nowak, and Peter Nielaba — Department of Physics, University of Konstanz, Germany

By numerically solving the stochastic Landau-Lifshitz-Gilbert (LLG) equation, computer simulations can be performed on a classical atomistic spin model. Spin torque effects can be taken into account by further inclusion of an adiabatic and a non-adiabatic torque term [1]. Due to the computational expense of atomistic simulations, system sizes are restricted to a nanometer range, so that micromagnetic approaches are desirable. However, conventional micromagnetic calculations for larger system sizes lack the correct description of temperature effects because of the assumption of a constant magnetisation length.

An alternative novel approach to investigate realistic systems sizes including temperature effects is to employ the so-called Landau-Lifshitz-Bloch (LLB) equation [2]. This equation forms a new basis for micromagnetic calculations at elevated temperatures using a macro spin model [3], where longitudinal relaxation processes are taken into account. We extend the LLB equation of motion by adding spin torque terms and study domain wall motion under the influence of current and temperature in permalloy films. Domain wall velocities show a strong temperature dependence.

[1] C. Schieback et al. EPJ B 59, 429 (2007). [2] D. A. Garanin PRB 55, 3050 (1997). [3] N. Kazantseva et al. PRB 77, 184428 (2008).