New math explains how nanowire magnetism shifts with shape
Researchers have solved a long-standing puzzle in nanowire physics: how curved wires change the behavior of magnetic interactions at the atomic level. The breakthrough simplifies predictions for ferromagnetic nanowires and could accelerate development of next-generation data storage and magnetic sensors that rely on precise control of these interactions.
Originaltitel: Reduced theory of symmetric and antisymmetric exchange interactions in nanowires
<p>We investigate the behavior of minimizers of perturbed Dirichlet energies supported on a wire generated by a regular simple curve gamma and defined in the space of S2-valued functions. The perturbation K is represented by a matrix-valued function defined on S2 with values in R3x3. Under natural regularity conditions on K, we show that the family of perturbed Dirichlet energies converges, in the sense of Gamma-convergence, to a simplified energy functional on gamma. The reduced energy unveils how part of the antisymmetric exchange interactions contribute to an anisotropic term whose specific shape depends on the curvature of gamma. We also discuss the significant implications of our results for studies of ferromagnetic nanowires when Dzyaloshinskii-Moriya interaction (DMI) is present.</p>