Enhanced flux creep and nonequilibrium optical response in YBaCuO epitaxial films

Two novel flux creep related phenomena in YBa2Cu3O7-δ films are presented: a sharp onset of nonequilibrium optical response and a thermally activated electrical resistivity with logarithmic current dependence of the activation energy. This nonlinear current dependence is significantly different from the predictions of the standard flux creep model. © 1989.