CRITICAL FLUCTUATIONS AT THE SUPERCONDUCTING TRANSITION OF TMBA2CU3O7-DELTA THIN-FILMS IN TRANSVERSE AND LONGITUDINAL MAGNETIC-FIELDS

We report an investigation of the resistive transition from the normal to the mixed state of TmBa2Cu3O7-delta thin films in different orient ations of magnetic fields up to 13 T. The broadening of the transition and its specific shape obscures the superconducting phase transition line T-c(B). Using the renormalized theory for critical superconductin g fluctuations in the anisotropic three-dimensional Ginzburg-Landau mo del by R. Ikeda we obtained an excellent description of the upper part of the resistive transition in transverse magnetic fields. In the lon gitudinal orientation, the broadening of the superconducting transitio n in a magnetic field is significantly smaller, in qualitative agreeme nt with theory.