Subject Area C1: Development of Simulation Tools for Ferromagnetic Structures and Hybrid Systems
Guido Meier, Dietmar Möller, Michael Hinze
Simulations of physical phenomena connect analytical theories with experiments.
This enables not only the comparison between theory and experiment, but also accesses
parameters that cannot be proved experimentally. In metal-semiconductor hybrid structures
and ferromagnetic devices the magnetoresistance
plays a crucial role. In this subject area physicists, computer scientists and mathematicians
are working together to develop efficient simulation tools for ferromagnetic structures and hybrid systems.
Spatial power density distributions (top row) and phases (bottom row)
of six exemplary spin-wave eigenmodes of a 1 x 1 µm2 permalloy square of 16 nm thickness.
The understanding of the interplay between electrical current and magnetization is essential for the
development of novel devices such as memories.
Therefore the magnetization and the magnetoresistance in
nanostructured ferromagnets and semiconductors are simulated.
An important aspect that has not been simulated yet is the influence of temperature on the
magnetization dynamics in nanostructures
The simulation of real systems requires the extension and acceleration of existing programs
such as the software OOMMF for micromagnetic simulations or the package M3S
that has been developed within the Graduiertenkolleg.
Improved algorithms and parallelization should enable the use of supercomputers.
The solution of differential equations will be improved by using finite-element methods.
The simulation results shall be compared with experimental results of magnetic-force microscopy, Hall micromagnetometry,
ferromagnetic resonance, photoconductance spectroscopy and transport measurements.
J. S. Yuan and J. J. Liou,
"Semiconductor Device Physics and Simulation",
Plenum Publishing Corporation, New York, First Edition (1998).
M. Donahue and D. Porter,
"OOMMF User's Guide, Version 1.0",
Interagency Report NISTIR 6376, National Institute of Standards and Technology,
Gaithersburg, MD (September 1999).
M. Najafi, B. Krüger, S. Bohlens, M. Franchin, H. Fangohr, A. Vanhaverbeke,
R. Allenspach, M. Bolte, U. Merkt, D. Pfannkuche, D. P. F. Möller, and G. Meier,
"Proposal for a standard problem for micromagnetic simulations including spin-transfer torque,",
J. Appl. Phys. 105, 113914-1-113914-8 (2009).
Reconfigurable hardware for accelerating physical simulations
Modelling and simulation of the interplay between electrical current and magnetization
with finite-element methods
Influence of temperature on the magnetization dynamics in magnetic nanostructures
Time- and space-resolved measurements of the current-induced motion of magnetic vortices