Accurate determination of the Josephson critical current by lock-in measurements

Razmik A. Hovhannisyan; Olena M. Kapran; Taras Golod; Vladimir M. Krasnov

doi:10.3390/nano11082058

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arXiv · 2112.04320

Accurate determination of the Josephson critical current by lock-in measurements

Razmik A. Hovhannisyan·Olena M. Kapran·Taras Golod·Vladimir M. Krasnov

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Abstract

Operation of Josephson electronics usually requires determination of the Josephson critical current $I_c$, which is affected both by fluctuations and measurement noise. Lock-in measurements allow obviation of $1/f$ noise and, therefore, provide a major advantage in terms of noise and accuracy with respect to conventional dc-measurements. In this work we show both theoretically and experimentally that the $I_c$ can be accurately extracted using first and third harmonic lock-in measurements of junction resistance. We derive analytic expressions and verify them experimentally on nano-scale Nb-PtNi-Nb and Nb-CuNi-Nb Josephson junctions.

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Razmik A. Hovhannisyan, Olena M. Kapran, Taras Golod, Vladimir M. Krasnov. 2021-12-08. Accurate determination of the Josephson critical current by lock-in measurements. https://doi.org/10.3390/nano11082058

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