Nonmonotonous temperature dependence of Shapiro steps in YBCO grain boundary junctions.

Leonid S Revin,Andrey L Pankratov,Sergey A Pavlov,Alexey E Parafin,Dmitriy V Masterov

doi:10.3762/bjnano.12.95

Leonid S Revin, Andrey L Pankratov + Show 3 more

Open Access

https://doi.org/10.3762/bjnano.12.95

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Abstract

The amplitudes of the first Shapiro steps for an external signal with frequencies of 72 and 265 GHz are measured as function of the temperature from 20 to 80 K for a 6 μm Josephson grain boundary junction fabricated by YBaCuO film deposition on an yttria-stabilized zirconia bicrystal substrate. Non-monotonic dependences of step heights for different external signal frequencies were found in the limit of a weak driving signal, with the maxima occurring at different points as function of the temperature. The step heights are in agreement with the calculations based on the resistively–capacitively shunted junction model and Bessel theory. The emergence of the receiving optima is explained by the mutual influence of the varying critical current and the characteristic frequency.

Highlights

High-temperature superconducting (HTSC) Josephson junctions (JJs) are of great interest since many physical properties can be observed in dynamics during the changing the temperature within a wide range from nitrogen temperatures down to sub-kelvin, such as the phase diffusion regime [1,2,3], evidence for a minigap [4], and low-noise nano-junctions [5]
We investigate the temperature dependence of the first Shapiro step amplitude for an external signal with frequencies of 72 and 265 GHz acting on YBa2Cu3O7−δ 6 μm Josephson grain boundary junction
The heights of the steps are consistent with calculations based on the resistively–capacitively shunted-junction (RCSJ) model and are qualitatively described by Bessel functions

Summary

Introduction

High-temperature superconducting (HTSC) Josephson junctions (JJs) are of great interest since many physical properties can be observed in dynamics during the changing the temperature within a wide range from nitrogen temperatures down to sub-kelvin, such as the phase diffusion regime [1,2,3], evidence for a minigap [4], and low-noise nano-junctions [5]. Such abilities raise fundamental interest in HTSC JJs and an active search for ways to practically use such JJs. In recent years, the limiting characteristics of detectors and mixers based on HTSC JJs [6,7,8,9,10,11] have been actively studied.

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