Treating the I-V characteristics of low as well as high Tc superconductors in context with the pinning potential

Abstract

Abstract A method is presented for treating the I-V characteristics of superconductors in the flux creep regime in context with the effective pinning potential and its dependence on the transport current. Some common features are shown in the behavior of different (low, as well as high Tc) superconductors. This common behavior manifests itself in the very similar form of the reduced apparent effective pinning potential, U efa U 0a wnen plotted against the logarithm of the reduced current I I 0 . The apparent pinning potential, U0a and some reference current, I0 are used as scaling quantities. The analysis concerns two samples of multifilamentary low Tc superconductors NbTi and Nb3Sn, as well as two laboratory samples of high Tc YBa2Cu3O7-δ superconductors. The main result of the presented analysis is that the plot of U efa U 0a vs ln( I I 0 ) was found to be close to a straight line having a common negative slope d ( U efa U 0a ) d(ln( I I 0 )) = − 1 or all studied samples disregarded from the material and from the value of temperature and magnetic field. Some slight deviation from a straight line indicates a digression from the power law V≈In characteristics as shown in the case of the YBa2Cu3O7−δ material.