FIZIKA A 3 (1994) 1, 47-54

MEASUREMENTS OF I-V CURVES OF SUPERCONDUCTORS WITH SUBNANOVOLT RESOLUTION

ŽELJKO MAROHNIĆ
Institute of Physics of the University, P.O.Box 304, 41001 Zagreb, Croatia

Received 13 May 1994

A simple method for the measurements of I-V curves of superconductors with the voltage sensitivity of about 0.1 nV is described in some detail. The superposition of a very low sinusoidally varying alternating current I_A on much larger computer controlled direct current I_D is fed into the sample and the resulting signal from the phase sensitive amplifier numerically integrated yielding the I-V curve. The sensitivity of the method is demonstrated by measuring the I-V curve of an Ag-clad (Bi,Pb)₂Sr₂Ca₂Cu₃O_10+y tape. The experimental set-up employed in these measurements is also described and some possible uses of the method discussed.

UDC 537.311
PACS 74.25.Fy

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