Scaling of thermally activated dissipation in epitaxial YBa2Cu3O7- thin films

Abstract

We have measured the resistive transition of an epitaxial YBa2Cu3O7- thin film in the case of applied field parallel and perpendicular to the c-axis up to 8 T, respectively. When the peak temperature Tp where dR/dT has a peak is defined as the critical temperature, we find that the dissipative resistivity can be well fitted by thermally activated flux motion below Tp in the presence of a magnetic field. Meanwhile, the field dependence of the peak temperature Tp follows the clean limit Ginzburg-Landau formula. The temperature T and field H dependences of the activation energy U can be described as the formula U = U0(1 - T/Tp)nH-, where n = 1.5 and = 0.57 for H || ab and n = 1.4 and = 0.62 for H || c, showing a 3D behaviour.