Vortex kinks in superconducting films with periodically modulated thickness

We report magnetoresistance measurements through Nb films having a periodic thickness modulation. The cylinder shaped large-thickness regions of the sample, which form a square lattice, act as repulsive centers for the superconducting vortices. For low driving currents along one of the axes of the square lattice, the resistivity \(\rho\) increases monotonously with increasing magnetic field \(B\) and the \(\rho\)--\(B\) characteristics are approximately piecewise linear. The linear \(\rho\) vs \(B\) segments change their slope at matching fields where the number of vortices is an integer or a half integer times the number of protruding cylinders in the sample. Numerical simulations allow us to associate the different segments of linear magnetoresistance to different vortex-flow regimes, some of which are dominated by the propagation of discommensurations (kinks).