Electrical Transport and Noise Properties of [100]-Tilt ${\hbox{YBa}}_{2}{\hbox{Cu}}_{3}{\hbox{O}}_{7{-}{\rm x}}$ Grain-Boundary Junctions With High $I_{c}R_{n}$ Product

Abstract

We have studied electrical transport and low-frequency noise properties of [100]-tilt bicrystal YBa 2 Cu 3 O 7 x junctions, which show a lower degree of structural disorder and higher characteristic voltages in comparison with conventional [001]-tilt grain-boundary junctions. The oxygen content of the junction barrier was varied by an annealing in atomic oxygen and by aging in molecular oxygen. The modification of the curves and low-frequency noise were monitored. The terahertz losses in the junctions were derived and were shown to decrease with the increase of the oxygen content. It was found that the resistance and critical current fluctuations are completely antiphase correlated and intensities of normalized resistance and critical current low-frequency fluctuations are equal in these junctions. Consequently, quasiparticles and Cooper pairs in the [100]-tilt junctions tunnel directly through the same parts of the barrier, and a band-bending model with the charge fluctuations at the barrier can applied to explain the modification of the [100]-tilt grain-boundary junctions after oxygen loading and aging.

Broadband THz Detection by YBaCuO Josephson Junctions Having Finite Capacitance

“…Technologically this task can be solved by adjusting the geometry of the junction, in particular by the film thickness. IC and RN parameters can also be changed by low-temperature annealing of bicrystal junctions in ozone atmosphere [17], annealing in atomic oxygen [18] and by oxygen aging [19]. In [10] the results of numerical simulations for the responsivity as well as noise-equivalent power (NEP) was obtained in the framework of RSJ model with thermal noise.…”

A broadband detector based on series YBCO grain boundary Josephson junctions

“…In addition, reducing the current noise of JJs can improve NEP and increase the benefit from linking junctions into a series chain. For this it is necessary, first, to perform synchronous detection at frequencies higher than 100 Hz, where the noise falls [ 45 ], and second, to reduce the noise by annealing the YBCO bicrystal junction in atomic oxygen [ 39 ].…”

“…where R d is the differential resistance; and depend on the nature of the junction barrier. For the considered structures, S I = 10 −12 was chosen as a typical value of the current fluctuations at a frequency of 100 Hz [ 39 – 40 ]. For fluctuations of bicrystal YBCO junctions, δ R N are mostly insignificant [ 31 , 41 – 42 ].…”

Signal performance of DC-SQUIDs with respect to YBCO thin film deposition rate

“…Fabrication of superconducting quantum interference devices (DC-SQUIDs) on high temperature superconducting YBa 2 Cu 3 O 7−ı (YBCO) thin films has been intensively studied for last decades in order to establish an appropriate technology essential for high performance devices [1][2][3][4][5][6]. A number of researches have been focused on the design and fabrication techniques in order to improve the noise performance and peak-to-peak voltage modulation depths of SQUIDs [7][8][9][10].…”

“…Even though the fabrication complexity of YBCO Josephson junctions has been simplified with bicrystal technology [11][12][13], the reliability of YBCO based SQUIDs is still the major challenge for many applications such as magneto-cardiography (MCG), susceptometry and non-destructive evaluation (NDE) [14][15][16]13]. The major limitations of YBCO SQUIDs are their relatively high 1/f noise levels, low output voltage modulation depths ( V) and low stability in time during room temperature storage and thermal cycles [4,6,17]. Most of them are related to the structural properties of YBCO thin films and junctions on them.…”