Current distribution in Y-Ba-Cu-O superconducting microbridges containing Π-shaped channel for easy vortex motion

A mixed state in dc-biased thin films of II-type superconductors realizes the Abrikosov magnetic vortices/ antivortices, which are the result of the current-self magnetic field penetration into the film at temperatures lower than its critical temperature T_c. A nucleation of vortices/antivortices at the superconducting film's edges, their motion perpendicular to the direction of biasing current, and the annihilation in the film's center originates from a current dissipation in the superconductor and expresses itself in experiments as a dc voltage. This work reports on the results of simulation of current density in a 50 μm wide, 100 μm long, and 0.3 μm thick YBa ₂Cu₃O_7-x microbridges containing Π-shaped 5 μm wide single channel of easy vortex motion fabricated by means of laser-writing technique. Analyzing a two-dimensional-net of resistors and assuming that, due to the Meissner-Ochsenfeld effect, the magnetic flux penetration into superconducting film is nonlinear, we demonstrate that presence of a Π-shaped channel causes a non-homogeneous distribution of current in the microbridge.