Vortex chains in superconducting nanowires

We have studied the superconducting properties of narrow aluminum nanowires in a magnetic field. As the magnetic field is increased, vortices enter the nanowire and self-organize in a periodic one-dimensional lattice. By tuning the width of the nanowire and the magnetic field, we can tune the vortex density, starting from a sparse array to a merging line of vortex cores in the center of the wire. We will discuss the phase diagram and the transport regimes in the current-voltage characteristics as a function of temperature and magnetic field.