Possible explanation for the shape of I-V curves of superconductors and a more meaningful definition of I/sub c/

A flux creep model is used to calculate the shape of the I-V characteristic of a superconductor. The functional form mimics an empirical equation, V approximately I/sup n/, frequently used to fit data, and thus offers a physical justification for its application. The magnetic field dependence of the exponent n is also predicted and compared with experiments. The fits so obtained are encouraging, but call for some experiments specifically designed to test all of the ramifications of the proposed model.>