Activation Energy of Bi2Sr2Ca1−xErxCu2O8+d Epitaxial Thin Films

The scaling behavior of the effective activation energy U(T, H) of epitaxial oriented Bi2Sr2Ca1−xErxCu2O8+d thin films with 0≤x≤0.10 has been studied as function of temperature and magnetic field. It has been found that the activation energy scales as U(H, T)=U0(1−t)mHn with exponent m=1.20±0.03 and n=−1/2. The field and temperature dependence of the activation energy, as well as its overall magnitude, is consistent with a model in which U(T, H) arises from plastic deformations of viscous flux liquid above the vortex-glass transition temperature.