Experimental determination of the fluctuational dissipation in YBCO films in tilted magnetic fields

We report on several sets of resistive transitions in YBCO twinned films, as a function of temperature T, magnetic field strength H and orientation theta of the field with respect to the CuO planes. It is shown that the magnetoresistivity exhibits an angular scaling behaviour in the upper part of the transitions, above a field-dependent temperature T-f(H); the scaling function is found to be in excellent agreement with the appropriate one for a strongly coupled layered superconductors. From these features, we argue that, in the scaling region, the dissipation is due to intrinsic mechanisms, such as fluctuations, even in twinned sample; to support this hypothesis, it is shown that the interacting fluctuations theory describes well the resistive behaviour for T > T-f.