Stacked niobium Josephson junction arrays under x-band irradiation

Abstract

Stacked Josephson junction arrays located at the rf current antinodes of a superconducting microstripline resonator were investigated.The circuits were designed t o obtain highly accurate voltages at cm-waveband microwave driving and low rf-power level. Nb-Al/AlO,-Nb Josephson junctions with tunneling area of 60 pm x 300 p m and critical current density up to 7A/cm2 were used. We compared the average voltages of the rf induced maximal current steps in arrays with up to three junctions per stack. Quantized current steps up to 300 mV were observed under microwave irradiation at frequency of 19.20 GHz in circuits with 384 three-junction stacks. The dynamics of stacked tunnel junctions in the presence of rf-currents will be discussed with respect to application as voltage standards .

Three-dimensional arrays of BiSrCaCuO-2212 intrinsic Josephson junctions and zero-crossing Shapiro steps at 760 GHz

“…For example, a few thousand or a few tens of thousand junctions in series to each other are required in quantum voltage standard to get zero-crossing Shapiro steps at sufficiently high voltages for 1 V or 10 V standard calibrations 5,6 . With Nb-based junctions both two-dimensional (2D) and three-dimensional (3D) arrays have been reported using a stacked-junction fabrication technique 7,8 , remarkably increasing the package density. And the purpose of the work to be discussed here is to develop similar structures using high temperature single crystals so that the possibilities intrinsic junctions provide us with can be fully explored.…”

Meandering bicrystal Josephson junction arrays in a hemispherical Fabry–Perot resonator

“…This provides parallel feeding of microwave power to all junctions [13]. Microstrip [17] and waveguide resonators were previously explored for irradiation of the JJ array at frequencies below 40 GHz [18].…”

Static properties of stacked Josephson junctions: Comparison of experiments with the inductively coupled sine-Gordon model

“…Another application that could benefit from junction stacking is the Josephson voltage standard. 3 The model that we assume to describe the static and the dynamic behavior of stacked Josephson junctions is the coupled sine-Gordon system. 4 We emphasize that also the intrinsic Josephson effect in high-T c superconductors 5 by now seems to be well described by this model, and therefore the low-T c artificial stacks can well serve as model systems for natural high-T c stacks.…”