V–VxOy–Pb Josephson tunnel junctions of high stability

Seifarth, H.; Rentsch, W.

doi:10.1002/pssa.2210180110

Cited by 14 publications

(5 citation statements)

References 21 publications

(1 reference statement)

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“…In particular the origin of such large conductance is likely related to the presence of vanadium. Similar high subgap conductances have been observed in several occasions in V-based tunnel junctions 40 – 44 , as well as in Nb-based tunnel junctions 45 .…”

Section: Resultssupporting

confidence: 86%

High operating temperature in V-based superconducting quantum interference proximity transistors

Ligato

Marchegiani

Virtanen

et al. 2017

Sci Rep

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Here we report the fabrication and characterization of fully superconducting quantum interference proximity transistors (SQUIPTs) based on the implementation of vanadium (V) in the superconducting loop. At low temperature, the devices show high flux-to-voltage (up to 0.52 mV/Φ0) and flux-to-current (above 12 nA/Φ0) transfer functions, with the best estimated flux sensitivity ~ 2.6 μΦ0/(Hz)1/2 reached under fixed voltage bias, where Φ0 is the flux quantum. The interferometers operate up to T bath 2 K, with an improvement of 70% of the maximal operating temperature with respect to early SQUIPTs design. The main features of the V-based SQUIPT are described within a simplified theoretical model. Our results open the way to the realization of SQUIPTs that take advantage of the use of higher-gap superconductors for ultra-sensitive nanoscale applications that operate at temperatures well above 1 K.

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Section: Resultssupporting

confidence: 86%

High operating temperature in V-based superconducting quantum interference proximity transistors

Ligato

Marchegiani

Virtanen

et al. 2017

Sci Rep

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“…Up t o the gap voltage of lead the generated power in the barrier is small and the temperature of the junction is given with sufficient accuracy by the temperature of the helium bath. For the tunnel junction whose properties we will discuss in more detail in this work we have measured The measurement of the critical current of the junctions in dependence on the magnetic field is carried out by the method described in [16]. I n the measurement a current linearly increasing with time flows through the junction and is switched of immediately after the jump of the voltage a t the critical current.…”

Section: Resultsmentioning

confidence: 99%

“…The temperature dependence of j o is given by the relations of Ambegaokar and Baratoff [12 to 141. For the London penetration depths the well-known relation [16] is used with &,+ as the penetration depth at 0 K and Tci as the critical temperature of the superconducting films.…”

Section: Discussion Of the Theoretical Relationsmentioning

confidence: 99%

The critical current of miniature thin film Josephson junctions with high current densities

Dettmann

Weber

1980

Phys. Stat. Sol. (a)

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Nb-Nb0,-Pb tunnel junctions with areas of about 10 x 10 pm2 and high current densities are prepared by cleaning the niobium surface in a rf glow discharge. The dependence of the critical Josephson currents on magnetic field is investigated. To a first approximation the behaviour of the critical current is described by the theory of one-dimensional junctions. Critical current densities up t~ 2 x 105 A/cma are reached. Nb-NbO,-Pb-Tiinnelverbindui~genmit Fliichen von etwe 10 X 10 ym2 und mit hohen Strorndichten werden durch Reinigen der Nioboberflache in einer HF-Glimmentladung hergestellt. Die Abhingigkeit des kritischen Josephsonstromes vom Magnetfeld wird untersucht. In erster Niiherung wird das Verhalten des kritischen Stromes durch die Theorie fur eindimensionale Tunnelverbindungen beschrieben. Es werden kritische Stromdichten bis zii 2 x 105 A/cm2 erreicht. F. DETTMAXN and P. B. WEBER where y is the phase difference between the two superconductors and [8 to 101is the Josephson penetrat*ion depth, 4 and 1, are the London penetration depths, dl and d, the thicknesses of the electrode films, t is the thickness of the barrier, jo the maximum current density, Go the flux quantum, and pcco the free space permeability. The current density in bhe barrier is given by

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“…The temperature dependence of the tunnel junction resistance we obtained a t intermediate temperatures can be compared with the analogous dependences in [GI (last row in Table 2). For tunnel resistances of the same order of magnitude the region where resistance changes essentially, occurs a t higher temperatures (= 200 "I<) [6]. This is perhaps due to different conipositions of t'he vanadium oxide films conditioned by different oxidation regimes which are hard to cont,rol and reproduce.…”

Section: Parameters Of Effective Potential Barriermentioning

confidence: 99%

“…Ilis gap estimate was quite rough since even a t eU2 = d p b + + A, the I ( U ) peculiarities were not sharp enough. Recently [6] characteristics of comparatively low-resistance R, 2 : (lo-, to 1) t 2 V-V,O,-Pb tunnel junctions have been obtained. It was shown that stable Josephson tunnel junctions based on vanadium and its oxides can be made for application in various electronic devices, though the physics of the tunnel effect in these junctions has not received sufficient consideration.…”

Section: Introductionmentioning

confidence: 99%

Tunnel effect in films of vanadium and its oxides

Yanson

Rybal'chenko

1975

Phys. Stat. Sol. (a)

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The tunnel junction properties of V–VxOy–Pb are investigated. Vanadium served as a basic film of the junctions. It was evaporated onto a glass substrate using an electronbeam heater. To form the barrier layer vanadium was oxidized in oxygen using a glow discharge. The current‐voltage characteristics of these junctions and their first and second derivatives are studied. A specific feature in the I–U characteristics is observed at energies ΔPb – ΔV, which earlier could not be observed because of a great excess current through the junction and permits a direct measurement of the vanadium superconducting gap 2ΔV and the construction of its temperature dependence which coincides with the BKS theory with sufficient accuracy. The temperature dependence of the tunnel junction resistance is studied in a wide temperature range. The forbidden band width is measured for vanadium oxide and gives Eg = (0.1 to 0.3) eV. The tunnel junctions obtained do not change their characteristics under long‐term preservation at normal conditions.

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V–VxOy–Pb Josephson tunnel junctions of high stability

Cited by 14 publications

References 21 publications

High operating temperature in V-based superconducting quantum interference proximity transistors

High operating temperature in V-based superconducting quantum interference proximity transistors

The critical current of miniature thin film Josephson junctions with high current densities

Tunnel effect in films of vanadium and its oxides

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