Nanomaterials 2024, 14, 420
Authors: Igor Bogush, Vladimir M. Fomin and Oleksandr V. Dobrovolskiy
Abstract: In planar superconductor thin films, the places of nucleation and arrangements of moving
vortices are determined by structural defects. However, various applications of superconductors
require reconfigurable steering of fluxons, which is hard to realize with geometrically predefined
vortex pinning landscapes. Here, on the basis of the time-dependent Ginzburg–Landau equation, we
present an approach for the steering of vortex chains and vortex jets in superconductor nanotubes
containing a slit. The idea is based on the tilting of the magnetic field B at an angle α in the plane
perpendicular to the axis of a nanotube carrying an azimuthal transport current. Namely, while
at α = 0◦, vortices move paraxially in opposite directions within each half-tube; an increase in α
displaces the areas with the close-to-maximum normal component |Bn| to the close(opposite)-to-slit
regions, giving rise to descending (ascending) branches in the induced-voltage frequency spectrum
fU(α). At lower B values, upon reaching the critical angle αc, the close-to-slit vortex chains disappear,
yielding fU of the n f1 type (n ≥ 1: an integer; f1: the vortex nucleation frequency). At higher B values,
fU is largely blurry because of multifurcations of vortex trajectories, leading to the coexistence of a
vortex jet with two vortex chains at α = 90◦. In addition to prospects for the tuning of GHz-frequency
spectra and the steering of vortices as information bits, our findings lay the foundation for on-demand
tuning of vortex arrangements in 3D superconductor membranes in tilted magnetic fields.
