XXIX International Symposium "Nanophysics and Nanoelectronics", Nizhny Novgorod, March 10-14, 2025
Superconductivity

Suppression of Fiske steps in long Josephson junction

A. A. Atepalikhin^ab, F. V. Khan^ab, L. V. Filippenko^a, V. P. Koshelets<sup>a

a</sup> Kotelnikov Institute of Radioengineering and Electronics of the Russian Academy of Sciences, Moscow
^b Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Moscow Region

Abstract: In this paper, we test a method for suppressing Fiske steps on the current-voltage characteristic of a long Josephson junction using matched load at its non-radiating end. The matched load is a four-stage Chebyshev transformer made of four sections of microstrip lines. The upper electrode of matched load is made of normal metal. The material chosen is molybdenum with a thickness of about 100 nm, which is a normal metal at the experiment temperature. Suppression of the Fiske steps will partially enable continuous tuning of the oscillator frequency at arbitrary bias current, including operating points in the resonant mode. Smoothing of the steps will lead to the expansion of the frequency range of the oscillator operation. We demonstrate that with the help of the proposed modification it was possible to smooth the Fiske steps on the current-voltage characteristics of the long Josephson junction and increase the range of voltages, in which it is possible to generate a signal with the power sufficient for use in heterodyne receivers.

Keywords: superconducting electronics, flux-flow oscillator, submillimeter-range oscillator, Fiske steps suppression.

Received: 06.03.2025
Revised: 06.03.2025
Accepted: 05.05.2025

DOI: 10.61011/FTT.2025.07.61181.21HH-25

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