Low Temperature Physics: 45, 776 (2019); https://doi.org/10.1063/1.5111306
Fizika Nizkikh Temperatur: Volume 45, Number 7 (July 2019), p. 906-915    ( to contents , go back )

About a possibility of faster detection of magnetic flux changes in a single-photon counter by RF SQUID with MoRe–Si(W)–MoRe junction

A.P. Shapovalov1,4, V.E. Shaternik2, O.G. Turutanov3, V.Yu. Lyakhno3, and V.I. Shnyrkov4

1Институт сверхтвердых материалов им. В.Н. Бакуля НАН Украины ул. Автозаводская 2, г. Киев, 04074, Украина
E-mail: shapovalovap@gmail.com

2Институт металлофизики им. Г.В. Курдюмова НАН Украины бульв. Академика Вернадского, 36, г. Киев, 03142, Украина

3Физико-технический институт низких температур им. Б.И. Веркина НАН Украины пр. Науки, 47, г. Харьков, 61103, Украина
E-mail: turutanov@ilt.kharkov.ua

4Киевский академический университет, бульв. Академика Вернадского, 36, г. Киев, 03142, Украина
pos Анотація:

Received January 17, 2019 г., revised March12, 2019 г., published online May 28, 2019

Abstract

The nonhysteretic regime of an RF SQUID with MoRe–Si(W)–MoRe Josephson junction is analyzed in order to detect the states of a single photon counter based on a superconducting quantum interferometer with discrete Hamiltonian. The absorption of a photon with 10 GHz frequency brings the counter to the excited level causing tunneling into the adjacent potential well and a change in the magnetic flux in the interferometer, which can be detected by the SQUID magnetometer. Measurement of a quantum system requires minimization of the back action of the signal readout channel at the counter, high sensitivity and speed of the magnetometer. The MoRe–Si(W)–MoRe contacts are optimized for the tungsten (W) concentration in silicon (Si) and the barrier layer thickness. It is shown that using MoRe–Si(W)–MoRe contacts with tungsten con-centration of about 11% for the RF SQUID at excitation frequency of about 1 GHz makes it practically an ideal parametric upward frequency shifter with noise determined by the cooled amplifier.

Key words: Josephson contact, tunnel junction, barrier doping, RF SQUID, single photon counter.

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