Intersecting Aslamazov–Larkin and hopping conduction in superconducting RE-123

Abstract

The coherence lengths of three superconductors have been extracted in the framework of Aslamazov–Larkin (AL) equation. A superconductor with an upturn in the normal state is found to have a very high coherence length in comparison to that of the two others with metallic normal states. We have suggested that an approximated Aslamazov–Larkin (AL) equation can be used to express the resistivity as a function of temperature in the paracoherent region. Our suggested form for ρAL (T) has been compared with the experimental resistivity ρ(Τ) to extract the coherence length in NBCO. An intersection of the suggested ρAL (T) and the variable range hopping (VRH) conduction ρVRH (T) has been observed to be sensitive to the coherence length. The ratio of the localization length and the coherence length is found to be very effective in shifting of crossing point towards the onset critical temperature in NBCO.