Matteucci Effect and Single Domain Wall Propagation in Bistable Microwire under Applied Torsion

摘要

Systematic experimental results on the Matteucci effect in torsioned magnetostrictiveFeSiB microwire are introduced, observed during the propagation of asingle domain wall (DW) under the action of axial driving magnetic field, H_(dr).These data are discussed, reviewing current bibliography models and proposingnew perspectives. The unidirectional DW velocity is quantified by voltage inducedin tiny pickup coils along the microwire. The Matteucci electromotive force (emf )induced between the microwire’s ends is associated with depinning and annihilationof the DW, introducing a new method to measure DW velocity. The emfamplitude is proportional to the DW velocity and the time derivative of theazimuthal magnetization, tailored by applied torsion. The data confirm theexistence of net values of azimuthal magnetization and spontaneous torsioninduced during fabrication. The clockwise/counterclockwise applied torsiondependence of Matteucci emf and DW velocity are experimentally determined forparallel and antiparallelH_(dr). Asymmetric behaviors are observed for both, the senseof applied torsion and the direction of H_(dr). The experimental data are discussed interms of the magnetoelastic anisotropy introduced by torsion. Through analysis ofthe DW dynamics, such asymmetric behaviors are interpreted as a magnetochiraleffect derived from the change of chirality of the propagating wall.