Fluctuational dissipation in YBa2Cu3O7-delta in tilted magnetic fields

We recently showed through angular measurements that in a wide range of temperature across T-c the resistivity of twinned films of YBa2Cu3O7-delta can be consistently described in terms of fluctuational conductivity. Comparison with data taken on untwinned samples reveals that the upper part of the transition is identical for films and single crystals, and that the same theory works well in both cases. In addition, pure nus How may describe the data in an appreciable region of H and T in the crystal only. Wt conclude that in a wide portion of the H-T plane the dissipation is due solely to intrinsic properties (order-parameter fluctuations with a possible Aux-How contribution in the crystal), while only at lower temperatures does the pinning become relevant, as supported by the breakdown of the angular scaling.