The scaling analysis on effective activation energy in HgBa2Ca2Cu3O8+δ

We review the methods of calculating the effective energy Ueff(T,B,J) for both transport measurements and magnetic decay, and suggest a new resistivity expression that is compatible with both vortex glass theory and thermal assistant flux creep theory. Then we apply these methods in our HgBa2Ca2Cu3O8+δ single phase superconductor to obtain the activation energy. Transport results confirm that the magnetic field and temperature dependence of the Ueff(T,B) can be well described by our new model. Magnetic relaxation data shows that the current density dependence of Ueff(J) can be scaled onto a single curve following the vortex glass theory. The exponent obtained from the scaling law is 0.978 in the temperature range 4.2–60 K, close to the value of 7/9 in the regime of flux creep in large vortex bundles predicted by vortex glass theory.