A reduced model for domain walls in soft ferromagnetic films at the cross-over from symmetric to asymmetric wall types
Journal of the European Mathematical Society, Tome 16 (2014) no. 7, pp. 1377-1422
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We study the Landau-Lifshitz model for the energy of multi-scale transition layers – called "domain walls'' – in soft ferromagnetic films. Domain walls separate domains of constant magnetization vectors mα±∈S2 that differ by an angle 2α. Assuming translation invariance tangential to the wall, our main result is the rigorous derivation of a reduced model for the energy of the optimal transition layer, which in a certain parameter regime confirms the experimental, numerical and physical predictions: The minimal energy splits into a contribution from an asymmetric, divergence-free core which performs a partial rotation in S2 by an angle 2θ, and a contribution from two symmetric, logarithmically decaying tails, each of which completes the rotation from angle θ to α in S1. The angle θ is chosen such that the total energy is minimal. The contribution from the symmetric tails is known explicitly, while the contribution from the asymmetric core is analyzed in [7].
Classification :
49-XX, 35-XX, 78-XX
Keywords: Γ-convergence, concentration-compactness, transition layer, bifurcation, micromagnetics
Keywords: Γ-convergence, concentration-compactness, transition layer, bifurcation, micromagnetics
@article{JEMS_2014_16_7_a2,
author = {Lukas D\"oring and Radu Ignat and Felix Otto},
title = {A reduced model for domain walls in soft ferromagnetic films at the cross-over from symmetric to asymmetric wall types},
journal = {Journal of the European Mathematical Society},
pages = {1377--1422},
publisher = {mathdoc},
volume = {16},
number = {7},
year = {2014},
doi = {10.4171/jems/464},
url = {http://geodesic.mathdoc.fr/articles/10.4171/jems/464/}
}
TY - JOUR AU - Lukas Döring AU - Radu Ignat AU - Felix Otto TI - A reduced model for domain walls in soft ferromagnetic films at the cross-over from symmetric to asymmetric wall types JO - Journal of the European Mathematical Society PY - 2014 SP - 1377 EP - 1422 VL - 16 IS - 7 PB - mathdoc UR - http://geodesic.mathdoc.fr/articles/10.4171/jems/464/ DO - 10.4171/jems/464 ID - JEMS_2014_16_7_a2 ER -
%0 Journal Article %A Lukas Döring %A Radu Ignat %A Felix Otto %T A reduced model for domain walls in soft ferromagnetic films at the cross-over from symmetric to asymmetric wall types %J Journal of the European Mathematical Society %D 2014 %P 1377-1422 %V 16 %N 7 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4171/jems/464/ %R 10.4171/jems/464 %F JEMS_2014_16_7_a2
Lukas Döring; Radu Ignat; Felix Otto. A reduced model for domain walls in soft ferromagnetic films at the cross-over from symmetric to asymmetric wall types. Journal of the European Mathematical Society, Tome 16 (2014) no. 7, pp. 1377-1422. doi: 10.4171/jems/464
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