GENERALIZED INVERSION SCHEME FOR THE DETERMINATION OF ACTIVATION-ENERGIES FROM FLUX-CREEP EXPERIMENTS IN HIGH-T(C) SUPERCONDUCTORS

For thermally activated flux creep, which can be characterized by a temperature-, magnetic-field-, and current-density-dependent activation energy U(j, T; B(e)), we show that this function can be determined from a combination of magnetization and magnetization dynamical relaxation rate data. As an illustration the method is applied to creep data on epitaxial YBa2Cu3O7 thin films. In contrast to previously proposed procedures, the present inversion scheme is much more general as it does not require a priori assumptions about the explicit temperature or field dependence of U.