An instrument for automatic measurements of critical current of superconductors in pulse mode

S. C. Gadkari, S. K. Gupta
1999 Review of Scientific Instruments  
An instrument has been developed for direct measurement of critical current and plotting of current-voltage (I-V) characteristics of superconductors in pulse mode. For these measurements, current pulses of increasing height are applied to sample and the voltage developed across the sample is monitored using a low noise voltage measuring circuit. Different sources of error responsible for limiting accuracy of pulse measurements techniques are discussed. A compensation network has been developed
more » ... o reduce inductively induced voltages generated during pulse measurements, to negligible values. The instrument enables automatic critical current measurement with 1-10 V/cm criteria in pulse mode without a computer and has voltage sensitivity of 10 nV. Critical current as a function of temperature/magnetic field and I-V characteristics of Bi-2212 single crystal and Y-123 thin films have been plotted using the circuit and the results have been compared with those obtained using direct current measurements.
doi:10.1063/1.1149611 fatcat:jpxl46czcfbtrnl6rsfohqvkeu