Influence of Contact Resistance on Ic Measurement of Bi Based Oxide Superconductor

In a measurement of critical current (critical current density) using 4-probe method, a number of factors, such as contact resistance, influence the measurement results according to Ic increasing. In this study, using Bi based superconductor prepared by FZ method, influences of temperature and magnetic field on electrode contact resistance and influence of pulsating current conditions on critical current measurement were studied. Using the 10−5Ω cm2 sample we obtained almost same Ic in the conditions of pulsating current in the range of 50~ 2000msec. On the other hand, samples with high contact resistivities were melt in the conditions of long pulsating current. Moreover we observed the microstructure with the immediate vicinity of contact by EPMA analysis.