Scaling of vortex transport properties and nonlinear ac response of high-temperature superconductors

: The macroscopic behavior of high-temperature superconductors is described by a nonlinear response function in combinations with Maxwell equations. This function is compatible with the suggested different model pinning barriers U ( J ). A comparison of this function to the scaling behavior of the isothermal current-voltage characteristics measured in twinned YBa 2 Cu 3 O (YBCO) samples shows fair agreement. We also compare the amplitude dependence of ac susceptibility derived from this function with several experimental results of high-temperature superconductors and find a general power law in the out-of-phase peak shift.