Table 1 Most common DMI types with the corresponding symmetry class and DMI vectors.

From: magnum.np: a PyTorch based GPU enhanced finite difference micromagnetic simulation framework for high level development and inverse design

DMI type

Symmetry class

Formula

DMI vectors \(\varvec{e}^\text {dmi}\)

Interface

\(C_\text {nv}\)

\(\varvec{h}^\text {dmi,i}\) \(= -\frac{2 \, D_i}{\mu _0 \, M_s} \; \left[ \nabla \left( \varvec{e}_z \cdot \varvec{m} \right) - \left( \nabla \cdot \varvec{m} \right) \, \varvec{e}_z\right]\)

\((\varvec{e}_y, -\varvec{e}_x, 0)\)

Bulk

T or O

\(\varvec{h}^\text {dmi,b}\) \(= -\frac{2 \, D_b}{\mu _0 \, M_s} \; \nabla \times \varvec{m}\)

\((\varvec{e}_x, \varvec{e}_y, \varvec{e}_z)\)

\(D_\text {2d}\)

\(D_\text {2d}\)

 

\((-\varvec{e}_x, \varvec{e}_y, 0)\)