Direct experimental visualization of magnetic flux guidance in artificially patterned YBa$_{2}$Cu$_{3}$O$_{7-x}$ thin films.

Development of new `fluxonic' devices, based on controlled motion of magnetic vortices, requires understanding of the principles of magnetic flux distribution and its dynamics in patterned superconductors. We investigated YBa$_{2}$Cu$_{3}$O$_{7-x}$ thin films equipped with various arrangements of antidots (holes of 1 $\mu $m radius) by means of real-time magneto-optical imaging. We demosntrate that 1D antidot arrays facilitate propagation of magnetic flux: each antidot concentrates the flux and tends to pass it on to the next antidot. Some flux from the antidot enters the superconductor creating a characteristic parabolic pattern. At high fields a whole line of antidots represents a cascade of parabolas with the centres in the holes. Flux `channels' and `reservoirs' were created in a superconducting strip by combining antidots of different size. We demonstrate that transfer of magnetic flux between two `reservoirs' lying parallel to the edge of the strip can be realized without applying additional transverse currents. At alternating magnetic field dynamics of the flux can be localized inside the `reservoirs'.