Voltage-current curves of high-temperature superconductor tapes measured at controlled current ramp rate compared with collective flux creep model

The voltage-current V(I) curve of high-temperature superconductor tapes as a function of current ramp rate R modelled by the collective flux creep model, with a power-law dependence of local electric field on current density, shows an approximate low-I relation V∝IR and a high-V relation V∝In. In order to compare experimental V(I) curves with the flux creep model prediction, a setup is designed with I provided by a dc power supply driven by an arbitrary waveform function generator and V and I data acquired synchronously by two nano-voltmeters. Some experimental results are given with their features discussed.