Some aspects of the motion of vortices in thin niobium films

Singularities in the temperature dependence of one of the characteristic values of the transport current at which unpinning of Abrikosov vortices took place were observed for thin niobium films prepared so that grain boundaries were oxidized. Anomalies were also found in the current-voltage characteristics of these films in a certain range of temperatures. These effects were explained by the interaction of rows of moving vortex filaments were an immobile quasiperiodic lattice of grain boundaries, dependent on the relative position and hardness of the vortex lattice