Associated People

J. Schröder, M. Reichel

Abstract

Magnetic materials make a key contribution to the energy transition in a wide range of technical applications. For example, particularly powerful permanent magnets can be used for efficient transportation in electric cars or energy conversion by means of wind generators to help cut greenhouse gases that are a threat to the climate. The current gold standard in the field of permanent magnets, in terms of performance, are NdFeB magnets. They currently deliver the highest energy product, but are prone to corrosion and higher temperatures, at which they quickly suffer high performance degradation. By adding heavy rare earths (HRE), such as dysprosium or terbium, these properties can be improved. Since the mining of HRE has dramatic consequences for the environment and the world market price is also very volatile, one goal is to reduce the portion of these elements and replace them with other abundant elements. Besides the stoichiometric composition of the materials, the underlying microstructure also has a decisive influence on the magnetic behavior. New process routes, such as severe plastic deformation (SPD) or additive manufacturing (AM), are intended to better control the production and targeted influence of these microstructures in the future. In this context, finite element-based simulations may help to predict the properties and the performance of the considered magnets. The theoretical framework is provided by the micromagnetism, which models the behavior of the magnetization vectors in the context of a phase field, enabling local domain wall motions and pinning mechanisms to be studied as well. The main challenges here are the non-convex constraints on the magnetization length and the fine discretization of the microstructures, which can be highly heterogeneous. The overall aim of this research, within the framework of the CRC/TRR 270 HoMMage, is to tailor strong and efficient magnets for green energy conversion.

References

M. Reichel, B.-X. Xu and J. Schröder, A comparative study of FE-schemes for micromagnetic simulations, Proceeding in Applied Mathematics and Mechanics, 21, e202100191 (2021).
J. Schröder, M. Reichel and C. Birk, An efficient numerical scheme for the FE-approximation of magnetic stray fields in infinite domains, Computational Mechanics 70, 141-153 (2022).
C. Birk, M. Reichel and J. Schröder, Magnetostatic simulations with consideration of exterior domains using the scaled boundary finite element method, Computer Methods in Applied Mechanics and Engineering 399, 115362 (2022).
M. Reichel, B.-X. Xu and J. Schröder, A comparative study of finite element schemes for micromagnetically coupled simulations, Journal of Applied Physics 132, 183903 (2022).
M. Reichel, J. Schröder and B.-X. Xu, Efficient micromagnetic finite element simulations using a perturbed Lagrange multiplier method, Proceeding in Applied Mathematics and Mechanics, accepted (2022).