Film thickness dependence of critical current characteristics of YBCO-coated conductors

The dependence of superconducting layer thickness on the critical current characteristics was investigated in the range of 0.5–1.5 μm for YBCO-coated conductors made by the PLD process. Since the dimension of the pinning is considered to be three as indicated by the pinning correlation length, it is concluded that the observed thickness dependence of the critical current density at low fields come simply from a degradation in the superconducting layer structure with increasing thickness. The irreversibility field and the n-value increase with the thickness. These dependencies are well described by the theoretical model of the flux creep and flow.