Effect of the dimensional crossover on critical currents and flux creep in YBa2Cu3O7/PrBa2Cu3O7 multilayers

Critical currents jc(T,H) and the flux creep rate dlnM/dlnt of YBa2Cu3O7/PrBa2Cu3O7 multilayers have been measured in a wide range of temperatures T. By taking different thicknesses of the PrBa2Cu3O7 separator layer the coupling strength between the CuO2 planes is controlled, thus making possible the crossover from the 3D to the 2D regime, when the superconducting properties and the dissipation processes are strongly influenced by fluctuations. The characteristic critical temperature T*c of the Larkin's theory for a quasi 2D superconducting layer determined from the flux creep data is in a good agreement with the T*c value found from the magnetoresistance measurements. (orig.)