69 research outputs found
Micromagnetics and spintronics: Models and numerical methods
Computational micromagnetics has become an indispensable tool for the
theoretical investigation of magnetic structures. Classical micromagnetics has
been successfully applied to a wide range of applications including magnetic
storage media, magnetic sensors, permanent magnets and more. The recent advent
of spintronics devices has lead to various extensions to the micromagnetic
model in order to account for spin-transport effects. This article aims to give
an overview over the analytical micromagnetic model as well as its numerical
implementation. The main focus is put on the integration of spin-transport
effects with classical micromagnetics
magnum.fe: A micromagnetic finite-element simulation code based on FEniCS
We have developed a finite-element micromagnetic simulation code based on the
FEniCS package called magnum.fe. Here we describe the numerical methods that
are applied as well as their implementation with FEniCS. We apply a
transformation method for the solution of the demagnetization-field problem. A
semi-implicit weak formulation is used for the integration of the
Landau-Lifshitz-Gilbert equation. Numerical experiments show the validity of
simulation results. magnum.fe is open source and well documented. The broad
feature range of the FEniCS package makes magnum.fe a good choice for the
implementation of novel micromagnetic finite-element algorithms
Efficient Energy-minimization in Finite-Difference Micromagnetics: Speeding up Hysteresis Computations
We implement an efficient energy-minimization algorithm for finite-difference
micromagnetics that proofs especially useful for the computation of hysteresis
loops. Compared to results obtained by time integration of the
Landau-Lifshitz-Gilbert equation, a speedup of up to two orders of magnitude is
gained. The method is implemented in a finite-difference code running on CPUs
as well as GPUs. This setup enables us to compute accurate hysteresis loops of
large systems with a reasonable computational effort. As a benchmark we solve
the {\mu}Mag Standard Problem #1 with a high spatial resolution and compare the
results to the solution of the Landau-Lifshitz-Gilbert equation in terms of
accuracy and computing time
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