VOLTAGE-CURRENT CHARACTERISTICS OF POLYCRYSTALLINE (BI,PB)(2)SR2CA2CU3O10 SUPERCONDUCTOR AT DIFFERENT MAGNETIC-FIELDS AND TEMPERATURES

The voltage-current characteristics of polycrystalline (Bi,Pb)(2)Sr2Ca 2Cu3O10 superconductor were investigated at temperatures from 80 to 10 5 K under magnetic field up to 0.4 T. In magnetic field considerable b roadening in the transition width occurs which depends on the processi ng conditions and microstructure of the sample. I-V data below T-c wer e fitted to a power law expression V similar to I-beta to obtain beta. We have found that beta decreases rather rapidly with increase of mag netic field and temperature, in low magnetic fields and at temperature s quite below T-c, respectively. Similar behavior was observed for the variation of the critical current as a function of temperature and ma gnetic field. The beta values are found to change linearly as a functi on of critical current at relatively law values of I-c.