A5025478049- Physics of Superconductivity and Magnetism
- Quantum and electron transport phenomena
- Superconductivity in MgB2 and Alloys
- Iron-based superconductors research
- Semiconductor Quantum Structures and Devices
- Advanced Chemical Physics Studies
- Superconducting Materials and Applications
- Rare-earth and actinide compounds
- Semiconductor materials and devices
- Ammonia Synthesis and Nitrogen Reduction
- Topological Materials and Phenomena
- Electronic and Structural Properties of Oxides
- Particle accelerators and beam dynamics
- Hydrogen Storage and Materials
- Advancements in Semiconductor Devices and Circuit Design
- Magnesium Alloys: Properties and Applications
- Mechanical and Optical Resonators
- Organic and Molecular Conductors Research
- Industrial Engineering and Technologies
- Surface and Thin Film Phenomena
- Magnetic and transport properties of perovskites and related materials
- Electric Power Systems and Control
- Copper Interconnects and Reliability
- Quantum, superfluid, helium dynamics
- Intermetallics and Advanced Alloy Properties
G.V. Kurdyumov Institute for Metal Physics
2012-2021
V. Bakul Institute for Superhard Materials
2021
National Academy of Sciences of Ukraine
1984-2006
Following the ever-rising demand for new functionalities and novel materials in superconducting circuitry, we provide a complete view on self-shunting problem Josephson junctions, relating it to specific features of multichannel weak link between electrodes where averaging over channels yields bimodal distribution transparencies with maxima near unity zero. We two examples such internally shunted devices, namely, four-layered Nb/Al-Al oxide-Nb junctions strongly disordered nanometer-thick...
Thin film heterostructures composed of superconducting electrodes (molybdenum rhenium alloy) and a nanoscale silicon layer doped with tungsten, have been designed experimentally studied. The current-voltage characteristics junctions exhibiting local maxima the current against background abrupt increases for first time, were measured in voltage range −800 to 800 mV, at temperatures 4.2–8 K. positions these singularities, which are symmetrical respect zero voltage, varied from sample within...
We have fabricated trilayered sandwiches consisting of superconducting electrodes made MoRe alloy with a critical temperature about 10 K and silicon interlayer thicknesses up to 20 nm doped by tungsten atomic concentrations at%. For below 5 at%, measurements transport characteristics revealed the presence charging energy in ultra-small dopant granules (the Coulomb-blockade effect) without any supercurrent through junction. Unexpectedly, persistent current at zero voltage bias has exposed...
We discuss an universal effect in tunnel characteristics of layered metal - insulator – structures, where the dielectric barrier is formed by a nanoscale disordered oxide film: distribution layer transparencies, which does not depend on specific microscopic it. Experimental results for superconducting three- and four-layered structures with inhomogeneous barriers, confirming existence are given jointly simple theoretical interpretation, based equipartition hypothesis product height way...
We have studied thin-film superconductor - semiconductor (with quantum dots)-superconductor MoRe-Si(W)-MoRe junctions, where electrons are tunneling through a single or several dots within the Si(W) barrier. Current-voltage characteristics (CVCs) of samples been measured in wide voltage range from -900 to 900 mV at temperatures 4.2 8 K. At relatively high tungsten content barrier, we observed emergence Josephson effect. Characteristic voltages I <sub...
This paper describes the established correlations between characteristics of MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -based superconducting materials and their structural features, in particular oxygen distribution content. As indicated by SEM Auger analysis, a sizeable amount is usually present (bulks, thin films, wires). The matrix phase bulk contains rather small amounts oxygen, but high dispersed inclusions or areas with...
We report a study of the electron tunneling transport in point-contact junctions formed by sharp Ag tip and two different highly correlated oxides, namely, magnetoresistive manganite La0.66Ca0.34MnO3 superconducting cuprate LaBa2Cu3O7−x. Strong chemical modifications oxide surface (supposedly, oxygen ion displacements) caused applying high voltages to have been observed. This effect is believed be responsible for an enormous growth inelastic processes across transition region that reveals...
Abstract Measurements of the microwave surface impedance for high-temperature superconductor YBa 2 Cu 3 O 7− x (YBCO) films irradiated by MeV Au 2+ ions at three irradiation doses (10 10 cm −2 , 11 and 12 ) were carried out different temperatures (below critical temperature T с ≈ 90 К) various rf current amplitudes use microstrip resonator technique. A noticeable decrease in resistance an enhancement linear response range low observed moderately film exposed to dose while higher increase a...
Thin-film MoRe–Si(W)–MoRe heterostructures consisting of superconducting electrodes (molybdenum-rhenium alloy) and a hybrid semiconductor tunnel barrier nanosized silicon layer with tungsten nanoclusters were fabricated experimentally studied. Current-voltage characteristics the measured in wide voltage range from −900 to 900 mV at temperatures 4.2 8 K, under applied magnetic fields microwave irradiation. We argue that temperature dependences critical current normal-state resistance might...
The nonhysteretic mode of a RF SQUID with MoRe–Si(W)–MoRe Josephson junction is analyzed in order to detect the states single-photon counter based on superconducting quantum interferometer discrete Hamiltonian. absorption photon 10 GHz frequency brings excited level causing tunnelling into adjacent potential well and change magnetic flux interferometer, which can be detected by magnetometer. Measurement system requires minimization back action signal read-out channel at counter, high...
Abstract We start with a short look at the problem of low-capacitance Josephson junctions, its history, and actual state-of-the-art. It is argued that such devices are important for applications requiring nonhysteretic current-voltage characteristics since reduction capacitance by several times makes it possible to increase device resistance same amount while keeping McCumber-Stewart damping parameter unaltered. Moreover, very high frequencies in RCSJ circuit parallel connection starts shunt...
The numerical model of long Josephson junctions with Gaussian spread critical currents has been developed. allowed calculating the IV-characteristics and power emission junctions. Zero-field steps in hysteretic region were found. When was comparable value averaged current, particularities corresponded to zero-field found derivative IV-characteristic far above region. Results qualitatively explained ranges existing theory IV-curves random distributions currents. applied for approximation...
Perspective for qubits Josephson Mo - Re alloy-oxide– Pb , alloy-normal metal–oxide– MoRe alloy, and NbN -normal junctions have been fabricated investigated.
The superconducting transition temperature of 140 nm ± 10 thin films on sapphire substrates, which were deposited by magnetron sputtering, was around 36 K. Using a magnetization technique, the film's critical current density estimated as <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J</i> <sub xmlns:xlink="http://www.w3.org/1999/xlink">C</sub> = 1.8 × <sup xmlns:xlink="http://www.w3.org/1999/xlink">7</sup> А/cm...
The critical current density at 4.2 and 20 K up to 15 T the temperature dependence of irreversible field have been studied in magnesium diboride wires bulks prepared from boron without with carbon addition. Structural investigations using X-ray microprobe analysis performed. A monofilamentary wire a round-shaped core manufactured containing 2 mol.% (approximate composition its matrix MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML"...
Superconducting structures of the superconductor-fullerene-superconductor type are prepared using thin films a molybdenum-rhenium alloy. The current-voltage characteristics obtained experimentally compared with theoretical calculated for models multiple Andreev reflections quasiparticles. nonuniform current flow through fullerene film is discussed.
Perspective Josephson Mo-Re alloy-oxide–Pb, alloy-normal metal–oxide–Pb and metal–oxide–normal metal–Mo-Re alloy junctions have been fabricated investigated. Thin (~50-100 nm) MoRe superconducting films are deposited on Al2O3 substrates by using a dc magnetron sputtering of target. Normal metal (Sn, Al) thin the surfaces thermal evaporation metals in vacuum oxidized to fabricate oxide barriers. Quasiparticle I–V curves were measured wide range voltages. To investigate transparency spread for...
The relevant pinning centers of Abrikosov vortices in MgB2-based materials are oxygen-enriched Mg-B-O inclusions or nanolayers and MgBx (x>4) phases. high critical current densities, jc, 106 103A/cm2 at 1 8.5 T, respectively, 20 K can be achieved polycrystalline (prepared 2 GPa) containing a large amount admixed oxygen. Besides, oxygen incorporated into the MgB2 structure small amounts (MgB1.5O0.5), which is supported by Auger studies calculations DOS binding energy. jc melt textured...