Double-Vortex-Assisted Asymmetric Magnetoreactance in H-Shaped Nanomagnets

We model the dynamical response of H-shaped layered nanostructures to the alternating current carried in a nonmagnetic substrate, which induces an alternating Oersted field inside the magnetic layer, in the presence of a static field transverse to the current-flow direction. The current is directed horizontally, whereas the field is vertical with respect to the H-letter shape of the structure. Reversal of the field induces a highly asymmetric transverse magnetoreactance in the magnetically soft nanomagnet due to the structure's double magnetic vortex. Micromagnetic simulations, for a specific resonant frequency of the alternating current, show the reactance change by over 100% in the vicinity of zero field, with a relatively large sensitivity to the magnetic field. The mechanism for the dynamical response of the nanomagnet is related to oscillations in the separation of the vortex cores.