I. E. Batov

Publications (13)2.75 Total impact

• Source

  Available from: Galina Strukova

  Dataset: 11JNN-3460-NSM-09

  G V Strukov, G K Strukova, I E Batov, M K Sakharov, E A Kudrenko, A A Mazilkin
• Source

  Available from: Galina Strukova

  Dataset: 11JNN-3460-NSM-09

  G V Strukov, G K Strukova, I E Batov, M K Sakharov, E A Kudrenko, A A Mazilkin
• Source

  Available from: M. Yu. Kupriyanov

  Article: Double proximity effect in hybrid planar superconductor-(normal metal/ferromagnet)-superconductor structures

  T. E. Golikova, F. Hübler, D. Beckmann, I. E. Batov, T. Yu. Karminskaya, M. Yu. Kupriyanov, A. A. Golubov, V. V. Ryazanov
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  ABSTRACT: We have investigated the differential resistance of hybrid planar Al-(Cu/Fe)-Al submicron bridges at low temperatures and in weak magnetic fields. The structure consists of a Cu/Fe bilayer forming a bridge between two superconducting Al electrodes. In the superconducting state of Al electrodes, we have observed a double-peak peculiarity in differential resistance of the S-(N/F)-S structures at a bias voltage corresponding to the minigap. We claim that this effect (the splitting of the minigap) is due to an electron spin polarization in the normal metal which is induced by the ferromagnet. We have demonstrated that the double-peak peculiarity is converted to a single peak at a coercive applied field corresponding to zero magnetization of the Fe layer.
  Phys. Rev. B. 08/2012; 86(6).
• Article: Supercurrent in Nb/InAs-Nanowire/Nb Josephson junctions

  H. Y. Gunel, I. E. Batov, H. Hardtdegen, K. Sladek, A. Winden, K. Weis, G. Panaitov, D. Gruetzmacher, Th. Schaepers
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  ABSTRACT: We report on the fabrication and measurements of planar mesoscopic Josephson junctions formed by InAs nanowires coupled to superconducting Nb terminals. The use of Si-doped InAs-nanowires with different bulk carrier concentrations allowed to tune the properties of the junctions. We have studied the junction characteristics as a function of temperature, gate voltage, and magnetic field. In junctions with high doping concentrations in the nanowire Josephson supercurrent values up to 100\,nA are found. Owing to the use of Nb as superconductor the Josephson coupling persists at temperatures up to 4K. In all junctions the critical current monotonously decreased with the magnetic field, which can be explained by a recently developed theoretical model for the proximity effect in ultra-small Josephson junctions. For the low-doped Josephson junctions a control of the critical current by varying the gate voltage has been demonstrated. We have studied conductance fluctuations in nanowires coupled to superconducting and normal metal terminals. The conductance fluctuation amplitude is found to be about 6 times larger in superconducting contacted nanowires. The enhancement of the conductance fluctuations is attributed to phase-coherent Andreev reflection as well as to the large number of phase-coherent channels due to the large superconducting gap of the Nb electrodes.
  05/2012;
• Article: Electronic transport in mesoscopic superconductor/2D electron gas junctions in strong magnetic field

  I. E. Batov, Th. Schaepers, N. M. Chtchelkatchev, A. A. Golubov, H. Hardtdegen, A. V. Ustinov
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  ABSTRACT: The hybrid superconductor/2D electron gas (S/2DEG) structures based on InGaAs-InP hetero-junctions with a high-mobility 2D electron gas and superconducting NbN electrodes have been investigated. The electronic transport and current-voltage characteristics of S/2DEG/normal metal (S/2DEG/N) structures in strong perpendicular magnetic fields have been studied. Oscillations in the magnetoresistance of S/2DEG/N structures have been found in strong magnetic fields. It is shown that at bias voltages lower than the superconducting gap the amplitude of oscillations in S/2DEG/N structures significantly exceeds the oscillation amplitude in the reference N/2DEG/N samples. The experimental results can be explained within the quasiclassical theory of magnetotransport in S/2DEG structures developed by N.M. Chtchelkatchev and I.S. Burmistrov (Phys. Rev. B, 2007, vol. 75, 214 510).
  Bulletin of the Russian Academy of Sciences Physics 04/2012; 73(7):880-882.
• Source

  Available from: Galina Strukova

  Article: Nanocrystalline Pd alloy films coated by electroless deposition.

  G V Strukov, G K Strukova, I E Batov, M K Sakharov, E A Kudrenko, A A Mazilkin
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  ABSTRACT: The structures of palladium and palladium alloys thin films deposited from organic electrolytes onto metallic substrates by electroless plating method have been investigated. The coatings are dense, pore-free 0.005-1 microm thick films with high adhesive strength to the substrate surface. EDX, XRD, SEM and TEM methods were used to determine the composition and structure of alloy coatings of the following binary systems: Pd-Au, Pd-Ag, Pd-Ni, Pd-Pb, and ternary system Pd-Au-Ni. The coatings of Pd-Au, Pd-Ag and Pd-Ni have a solid solution structure, whereas Pd-Pb is intermetallic compound. It has been found that the deposited films consist of nanocrystalline grains with sizes in the range of 11-35 nm. Scanning and transmission electron microscopy investigations reveal the existence of clusters formed by nanocrystalline grains. The origin for the formation of nanocrystalline structures of coating films is discussed.
  Journal of Nanoscience and Nanotechnology 10/2011; 11(10):8986-93. · 1.56 Impact Factor
• Source

  Available from: Martin Weides

  Article: Josephson supercurrent in Nb/InN-nanowire/Nb junctions

  R. Frielinghaus, I. E. Batov, M. Weides, H. Kohlstedt, R. Calarco, Th. Schaepers
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  ABSTRACT: We experimentally studied the Josephson supercurrent in Nb/InN-nanowire/Nb junctions. Large critical currents up to 5.7 $\mu$A have been achieved, which proves the good coupling of the nanowire to the superconductor. The effect of a magnetic field perpendicular to the plane of the Josephson junction on the critical current has been studied. The observed monotonous decrease of the critical current with magnetic field is explained by the magnetic pair-breaking effect in planar Josephson junctions of ultra-narrow width [J. C. Cuevas and F. S. Bergeret, Phys. Rev. Lett. 99, 217002 (2007)] Comment: 4 pages, 3 figures
  01/2010;
• Source

  Available from: Vasili Stolyarov

  Article: Josephson tunnel junctions with strong ferromagnetic interlayer

  A. A. Bannykh, J. Pfeiffer, V. S. Stolyarov, I. E. Batov, V. V. Ryazanov, M. Weides
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  ABSTRACT: The dependence of the critical current density j_c on the ferromagnetic interlayer thickness d_F was determined for Nb/Al_2O_3/Cu/Ni/Nb Josephson tunnel junctions with ferromagnetic \Ni interlayer from very thin film thicknesses (\sim 1 nm) upwards and classified into F-layer thickness regimes showing a dead magnetic layer, exchange, exchange + anisotropy and total suppression of j_c. The Josephson coupling changes from 0 to pi as function of d_F, and -very close to the crossover thickness- as function of temperature. The strong suppression of the supercurrent in comparison to non-magnetic \Nb/Al_2O_3/Cu/Nb junctions indicated that the insertion of a F-layer leads to additional interface scattering. The transport inside the dead magnetic layer was in dirty limit. For the magnetically active regime fitting with both the clean and the dirty limit theory were carried out, indicating dirty limit condition, too. The results were discussed in the framework of literature
  09/2008;
• Source

  Available from: N. M. Chtchelkatchev

  Article: Andreev reflection and strongly enhanced magnetoresistance oscillations in GaInAs/InP heterostructures with superconducting contacts

  I. E. Batov, Th. Schapers, N. M. Chtchelkatchev, H. Hardtdegen, A. V. Ustinov
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  ABSTRACT: We study the magnetotransport in small hybrid junctions formed by high-mobility GaInAs/InP heterostructures coupled to superconducting (S) and normal metal (N) terminals. Highly transmissive superconducting contacts to a two-dimensional electron gas (2DEG) located in a GaInAs/InP heterostructure are realized by using a Au/NbN layer system. The magnetoresistance of the S/2DEG/N structures is studied as a function of dc bias current and temperature. At bias currents below a critical value, the resistance of the S/2DEG/N structures develops a strong oscillatory dependence on the magnetic field, with an amplitude of the oscillations considerably larger than that of the reference N/2DEG/N structures. The experimental results are qualitatively explained by taking Andreev reflection in high magnetic fields into account. Comment: 5 pages, 5 figures
  04/2007;
• Source

  Available from: issp.ac.ru

  Article: Temperature and Frequency Dependence of Complex Conductance of Ultrathin YBa2Cu3O7−x Films: Observation of Vortex–Antivortex Pair Unbinding

  V.A. Gasparov, G.E. Tsydynzhapov, I.E. Batov, Qi Li
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  ABSTRACT: We have studied the temperature dependencies of the complex sheet conductance, (, T), of 1–3 unit cell (UC) thick YBa2Cu3O7–x films sandwiched between semiconducting Pr0.6Y0.4Ba2Cu3O7–x layers at high frequencies. Experiments have been carried out in a frequency range between: 2–30 MHz with one-spiral coil technique, in 100 MHz-1 GHz frequency range with a new technique using a single spiral coil cavity, and at 30 GHz by aid of a resonant cavity technique. The real, Re M(T), and imaginary parts of the mutual-inductance M(T, ), between a coil and a film, were measured and converted to complex conductivity by aid of the inversion procedure. We have found quadratic temperature dependence of the kinetic inductance, Lk–1 (T), at low temperatures independent of frequency, with a break in slope at TdcBKT, the maximum of real part of conductance and large shift of the onset temperature and the maximum 1(T) position to higher temperatures with increasing frequency . We obtain from these data the universal ratio TdcBKT/L–1k (TdcBKT) = 25, 25 and 17, nH K for 1, 2 and 3-UC films, respectively in close relation with theoretical prediction of 12 nH K for vortex–antivortex unbinding transition. The activated temperature dependence of the vortex diffusion constant was observed and discussed in the framework of vortex–antivortex pair pinning.
  Journal of Low Temperature Physics 01/2005; 139(1):49-63. · 1.19 Impact Factor
• Source

  Available from: arxiv.org

  Article: Temperature and Frequency Dependence of Complex Conductance of Ultrathin YBa2Cu3O7-x Films: A Study of Vortex-Antivortex Pair Unbinding

  V. A. Gasparov, G. Tsydynzhapov, I. E. Batov, Qi Li
  [show abstract] [hide abstract]
  ABSTRACT: We have studied the temperature dependencies of the complex sheet conductance of 1-3 unit cell (UC) thick YBa2Cu3O7-x films sandwiched between semiconducting Pr0.6Y0.4Ba2Cu3O7-x layers at high frequencies. Experiments have been carried out in a frequency range between: 2 - 30 MHz with one-spiral coil technique, 100 MHz - 1 GHz frequency range with a new technique using the spiral coil cavity and at 30 GHz by aid of a resonant cavity technique. The real and imaginary parts of the mutual-inductance between a coil and a film were measured and converted to complex conductivity by aid of the inversion procedure. We have found a quadratic temperature dependence of the kinetic inductance, L_k^-1(T), at low temperatures independent of frequency, with a break in slope at T^dc_BKT, the maximum of real part of conductance and a large shift of the break temperature and the maximum position to higher temperatures with increasing frequency. We obtain from these data the universal ratio T^dc_BKT/L_k^-1(T^dc_BKT) = 25, 25, and 17 nHK for 1-, 2- and 3UC films, respectively in close agreement with theoretical prediction of 12 nHK for vortex-antivortex unbinding transition. The activated temperature dependence of the vortex diffusion constant was observed and discussed in the framework of vortex-antivortex pair pinning. PACS numbers: 74.80.Dm, 74.25.Nf, 74.72.Bk, 74.76.Bz
  12/2004;
• Source

  Available from: A. A. Golubov

  Article: Andreev reflection and enhanced subgap conductance in NbN/Au/InGaAs-InP junctions

  I. E. Batov, Th. Schaepers, A. A. Golubov, A. V. Ustinov
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  ABSTRACT: We report on the fabrication of highly transparent superconductor/normal metal/two-dimensional electron gas junctions formed by a superconducting NbN electrode, a thin (10nm) Au interlayer, and a two-dimensional electron gas in a InGaAs/InP heterostructure. High junction transparency has been achieved by exploiting of a newly developed process of Au/NbN evaporation and rapid annealing at 400C. This allowed us to observe for the first time a decrease in the differential resistance with pronounced double-dip structure within the superconducting energy gap in superconductor-2DEG proximity systems. The effect of a magnetic field perpendicular to the plane of the 2DEG on the differential resistance of the interface was studied. It has been found that the reduced subgap resistance remains in high magnetic fields. Zero-field data are analyzed within the previously established quasiclassical model for the proximity effect. Comment: 15 pages, 5 figures
  09/2003;
• Source

  Available from: A. A. Golubov

  Article: Andreev reflection and enhanced subgap conductance in NbN/Au/InGaAs-InP junctions

  I. E. Batov, Th. Schäpers, A. A. Golubov, A. V. Ustinov
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  ABSTRACT: This version is available at the following Publisher URL: http://jap.aip.org