Transition form thermally activated to regular flow of magnetic flux vortices

The effect of the superconductor structure nonuniformities on the vortex medium flow in the case of weak magnetic fields at the temperatures from 78 up to 83 K in dependence on the current shift density is studied through the transport measurements of the Bi2Sr2CaCu2O8+x thin film microbridges. The obtained results are analysed within the frames of the theories on the current flux and regular flow of vortices. It is shown that the current dependences of the effective potential of the vortices pinning are with sufficient accuracy described within the frames of two statistical models. Both models contain as the threshold cases the modes of thermally activated and regular of vortices. It is established that in case of exceeding certain value by the magnetic field there takes place fast fall in the value and dispersion of the pinning potential, so that the regular flow mode begins already by low values of the shift current. The above fact is related to the event of the vortex filaments destruction into two-dimensional segments