EFFECT OF THE LORENTZ FORCE ON DISSIPATION IN YBA2CU3OX THIN-FILMS

The current-voltage characteristics of YBa2Cu3Ox (YBCO) thin films hav e been measured, with both current and magnetic field applied parallel to the ab-plane, to study the effect of the Lorentz force on dissipat ion. The angle (theta) between the field and the current is varied to obtain the angular dependence of the I-V curve. A power law behavior f or the I-V curves is observed for different fields and theta values st udied. The results cannot be explained on the basis of the existing nu x flow and flux creep models. A model for the vortex motion has been d eveloped to explain the results.