Thermal excitation measured by resistivity measurement on the Mg-doped high temperature superconductors

The thermal excitation that starts to occur from the opening temperature T* in the normal state of Mg-doped YBCO superconductors was studied by the re sistivity measurement. There are some characteristic temperatures T* and T- F related to the thermal excitation of quasi-particles during the cooling p rocess. The data of T-F are close to the onset temperature of the supercond uctors. The magnitude of the pseudo-gap (Delta (PG)) can be measured from t he In[1/rho (N)(T) - 1/p(T)] vs 1/T curve, it depends on the concentration of the magnesium.