Publications on the project |
004 AC response of 2H-NbSe2 single crystals with electron-irradiation-induced defects |
Authors: | E. Bartolome, J. Bartolome, A. Arauzo, V. V. Eremenko, V. A. Sirenko | |
Summary: | The generation of defects in NbSe(2) single crystals by electron irradiation has been investigated by a combination of ac susceptibility and structural measurements. Remarkably, thanks to the layered structure of NbSe(2), we show that electronic irradiation cannot only create point defects but also in-plane extended defects, which modify anisotropically the ac response. Indeed, the analysis of the onset of the nonlinear susceptibility response, H(ac)(l)(T), as a function of irradiation dose and field orientation shows a correlated increase in the density of anisotropic defects induced by electron irradiation. Also, we measured a decrease in the strength of the pinning (Labusch) constant α(L) accounting for elastic vortex oscillations within the linear Campbell regime for high-dose-irradiated samples in a transverse field, again compatible with the presence of planar defects hindering vortex pinning. X-ray powder diffraction and TEM electron diffraction measurements suggest these in-plane defects may result from the rupture of Se-Se bonds and the formation of nanorods and nanowires by NbSe(2) sheet rolling. | |
Keywords: | | |
Edition: | Journal of Physics: Condensed Matter | | | 2010,
P. 295702 ,English |
004 Distinctive features of thermal expansion of niobium diselenide |
Authors: | Gospodarev IA, Eremenko AV, Kravchenko KV, AF Sirenko, Sirenko VA, Sirkin ES, Feodosyev SB, Shabakaeva YA | |
Summary: | | |
Keywords: | | |
Edition: | Fizika Tverdogo Tela | | | 2013,
825-830,Russian |
004 Chiral tunneling in metallic carbon nanotubes |
Authors: | A.V. Parafilo, I.V. Krive, E.N. Bogachek, U. Landman, R.I. Shekhter, M. Jonson | |
Summary: | The concept of chiral tunneling in metallic single-wall carbon nanotubes, originating from the interplay of local electrostatic and pseudomagnetic potentials, is considered and applied to an evaluation of the Josephson current in a nanotube-based superconductor–normal metal–superconductor (SNS) junction and the persistent current in a circular nanotube. In the former case, an oscillatory dependence of the critical supercurrent on the potential strength and the nanotube chiral angle is predicted. In the latter case, the existence of a spontaneous persistent current in an isolated ringlike nanotube is discussed. | |
Keywords: | | |
Edition: | Phys. Rev. B. | | | 2011,
P.045427-1-045427-5,English |
004 Homogeneous 3He-4He solid solutions in the pre-separation region |
Authors: | T.N. Antsygina, A.A. Lisunov, V.A. Maidanov, V.Y. Rubanskyi, S.P. Rubets, E.Ya. Rudavskii, K.A. Chishko | |
Summary: | Temperature dependences of the pressure P(T) in homogeneous solid 3He–4He mixtures have been studied experimentally in the wide range of concentrations (35.0%, 62.0%, 68.3%, 74.1%, 75.0%, and 89.3% 3He) above and below the equilibrium phase separation temperature Ts. An anomalous behaviour of the pressure in the vicinity of Ts is found for all investigated samples. With decreasing temperature, as Ts is approached, the pressure increases instead of expected reduction due to decrease in the phonon contribution (Pph∼T4). Such an increase in pressure continues in the metastable region below Ts until the mixture separates. Theoretical interpretation of the observed effects based on a rigorous thermodynamic approach is proposed. The found experimentally pressure behaviour can be described only with the consistent account for fluctuations in the impurity subsystem which near Ts dominates over phonon contribution into the pressure. The obtained theoretical results are in good quantitative agreement with the experimental data. Density fluctuations in the concentrated mixtures give rise to a spontaneous formation of impuriton nano-clusters containing several hundreds of atoms. The fluctuation can be rigorously interpreted as a nucleus of the second phase in the pre-separated homogeneous solid mixture. The estimated size of the fluctuation nano-clusters agrees with the corresponding value for second phase nuclei obtained from the Lifshits–Slesov phenomenological theory of homogeneous nucleation. | |
Keywords: | 3He–4He solid mixtures; Density fluctuations; Phase separation | |
Edition: | Physica B: Condensed Matter | | | 2011,
3870-3875 ,English |
004 Magnetization of 3He layers in ferromagnetic regime: Cluster size effects |
Authors: | I.I. Poltavsky, T.N. Antsygina, M.I. Poltavskaya and K.A. Chishko | |
Summary: | Magnetization of pure 3He monolayers on graphite and solid 3He on 4He-preplated graphite in the ferromagnetic regime is investigated theoretically within a two-dimensional spin-1/2 Heisenberg model in an external magnetic field. We develop an analytical approach based on a second-order two-time Green function formalism which describes the thermodynamic functions for finite as well as for infinite spin systems in the whole temperature range at arbitrary fields h . In particular, the present theory provides a proper description of the magnetization in the intermediate temperature region h<T<J at h well below the exchange J, that is in the region where the measurements for solid 3He monolayers are usually made. It is known from the experiment that only a part of 3He atoms is involved into ferromagnetic exchange. The ferromagnetic spins form clusters whose size is a function of coverage. The coverage dependences of the exchange constant, saturation magnetization, and average cluster size are found and analyzed. Nonmonotonic variation of the exchange constant with coverage is discussed. The effect of the cluster size on the temperature dependence of the magnetization is studied. To clarify how the cluster shape and boundary conditions affect magnetic properties of nanoclusters we calculate numerically the magnetization of small magnetic systems using the exact diagonalization method. | |
Keywords: | Heisenberg model; Solid 3He monolayers; Ferromagnetic nanoclusters | |
Edition: | Physica B: Physics of Condensed Matter | | | 2012,
3925-3932,English |
004 Thomas precession, persistent spin currents and quantum forces |
Authors: | S. Ouvry, L. Pastur, A. Yanovsky | |
Summary: | We consider T-invariant spin currents induced by spin-orbit interactions which originate from the confined motion of spin carriers in nanostructures. The resulting Thomas spin precession is a fundamental and purely kinematic relativistic effect occurring when the acceleration of carriers is not parallel to their velocity. In the case where the carriers (e.g. electrons) have magnetic moment, the forces due to the electric field of the spin current can, under certain conditions, exceed the van der Waals-Casimir forces by several orders of magnitude. We also discuss a possible experimental set-up tailored to use these forces for checking the existence of a non-zero anomalous magnetic moment of the photon. | |
Keywords: | | |
Edition: | European Physics Letters | | | 2014,
18001 ,English |
004 Single-Electron Shuttle Based on Electron Spin |
Authors: | Kulinich S.I., Gorelik L.Y., Kalinenko A.N., Krive I.V., Shekhter R.I., Park Y.W., Jonson M. | |
Summary: | A nanoelectromechanical device based on magnetic exchange forces and electron spin flips induced by a weak external magnetic field is suggested. It is shown that this device can operate as a new type of single-electron “shuttle” in the Coulomb blockade regime of electron transport. | |
Keywords: | | |
Edition: | Phys. Rev. Letters | | | 2014,
117206-1-117206-4 ,English |
004 Polaronic effects and thermally enhanced weak superconductivity. |
Authors: | V. Parafilo, I. V. Krive, R. I. Shekhter, Y. W. Park, M. Jonson | |
Summary: | We theoretically analyze the d.c. Josephson current between two superconductors connected by a vibrating
weak link. Assuming the weak link to be a “quantum dot”, we predict that the critical current is thermally
enhanced at low temperatures if the electron-vibron interaction is strong and has an anomalous temperature
dependence in a large temperature interval. We estimate that this unusual behavior, which occurs because the
current through the weak link is carried by “polaronic” Andreev states, is measurable in experiments on, e.g.,
carbon-nanotube-based Josephson junctions. | |
Keywords: | | |
Edition: | Phys. Rev. B | | | 2014,
115138 ,English |
004 Exact Description of the Discrete Breathers and Solitons Interaction in the Nonlinear Transmission |
Authors: | M.M. Bogdan, D.V. Laptev | |
Summary: | For the nonlinear self-dual network equations and the equivalent Hirota lattice equation the pair collision processes of two discrete breathers, breather and one-parametric soliton (kink, antikink), breather and linear wave, one-parametric soliton and linear wave are described. The explicit expressions of the “kink-breather” and “breather-breather” solutions are constructed. The shifts of the center-of-masses and phases of the breather oscillations have been expressed in terms of the dynamical characteristics of linear and nonlinear excitations of the system. | |
Keywords: | | |
Edition: | Journal of the Physical Society of Japan | | | 2014,
064007 ,English |
004 Field dependence of magnetization for a thin ferromagnetic film on rough antiferromagnetic surface |
Authors: | A.Kovalev, M. Pankratova | |
Summary: | Simple theoretical models are proposed for the analytical and the numerical study of the exchange bias phenomenon in the layered systems with rough AFM/FM interface. It is shown that the qualitative type of the magnetization curves depend crucially on the variation of the roughness degree. We obtain that the magnetization curves are qualitatively of the same type in the cases of perfect and rough FM/AFM interfaces. The method which allow to identify the character of the interface (rough or perfect) is proposed. | |
Keywords: | Ferromagnetic; Antiferromagnetic; Rough interface; Exchange bias; Magnetization | |
Edition: | Superlattices and Microstructures | | | 2014,
275-280,English |
004 Variation of the deformation mechanisms in a nanocrystalline Pd-10 at.% Au alloy at room and cryogenic temperatures |
Authors: | Ivanisenko, Y., Tabachnikova, E.D., Psaruk, I.A., Smirnov, S.N., Kilmametov, A., Kobler, A., Kübel, C., Kurmanaeva, L., Csach, K., Mishkuf, Y., Scherer, T., Semerenko, Y.A., Hahn, H. | |
Summary: | For the first time, the details of plastic deformation in a nanocrystalline Pd–10 at.% Au alloy with an average grain size of 14 nm were investigated in compression tests over the temperature range between 4.2 and 300 K and the corresponding microstructural changes were analyzed. It was established that decreasing the grain size from 10 μm to 14 nm resulted in a 4.7–6.4 increase in the applied stress as the temperature was decreased from 300 to 77 K. However, a further decrease in the temperature did not lead to an additional increase in the applied stress in these nanocrystalline samples. The nanocrystalline samples revealed an extended microplasticity stage with parabolic strain hardening up to 4.2% strain at room temperature. With decreasing temperature, the strain range over which microplasticity occurred shrank and was down to 2% at 40 K. As the samples were deformed in the macroplastic regime, they demonstrated weak strain hardening at room temperature and at 210 K, but strain softening was instead observed at cryogenic temperatures down to 40 K. Subsequent microstructural investigations revealed that the strain hardening behavior was accompanied by significant grain growth indicating a reverse Hall–Petch relationship. Deformation curves at 10 K displayed serrated plastic flow. To explain the observed details of the deformation behavior of nc alloys, a specific deformation mechanism for the nc state is proposed where plasticity was governed by grain boundary sliding (GBS) and was accommodated by the slip of dislocations emitted from grain boundaries. This is based upon the fact that GBS allows for the stress concentration necessary for dislocation emission and that dislocations provide a way to accommodate geometric incompatibilities arising along the GBS path. | |
Keywords: | (A) Ductility; (A) Grain boundaries; (B) Polycrystalline material; (C) Mechanical testing; Cryogenic temperature | |
Edition: | International Journal of Plasticity | | | 2014,
40-57,English |
004 Nanoscale phase separation and cluster glass in Nd2 / 3Ca1 / 3MnO3 |
Authors: | A. Feher, M. Kajňaková, E.L. Fertman, A.B. Beznosov, V.A. Desnenko, S.N. Dolya | |
Summary: | | |
Keywords: | | |
Edition: | Nanosystems, nanomaterіals, nanotehnologіes | | | 2011,
189 – 196,Russian |
004 Sorption kinetics of 3He by fullerene C60. Quantum diffusion of 3He and 4He in fullerite |
Authors: | A.V. Dolbin, V.B. Esel'son, V.G. Gavrilko, V.G. Manzhelii, N.A. Vinnikov, S.N. Popov | |
Summary: | | |
Keywords: | | |
Edition: | JETP letters | | | 2011,
638–641,Russian |
004 Tunneling effects in the kinetics of helium and hydrogen isotopes desorption from single-walled carbon nanotube bundles |
Authors: | B. A. Danilchenko, I. I. Yaskovets, I. Y. Uvarova, A. V. Dolbin, V. B. Esel'son, R. M. Basnukaeva and N. A. Vinnikov | |
Summary: | The kinetics of desorption both helium isotopes and molecules of hydrogen and deuterium from open-ended or γ-irradiated single-walled carbon nanotube bundles was investigated in temperature range of 10–300 K. The gases desorption rates obey the Arrhenius law at high temperatures, deviate from it with temperature reduction and become constant at low temperatures. These results indicate the quantum nature of gas outflow from carbon nanotube bundles. We had deduced the crossover temperature below which the quantum corrections to the effective activation energy of desorption become significant. This temperature follows linear dependence against the inverse mass of gas molecule and is consistent with theoretical prediction. | |
Keywords: | | |
Edition: | Appl. Phys. Lett | | | 2014,
173109 ,English |
004 The study of creep and glass elastomers by Microindentation: epoxy and nanocomposites based on it |
Authors: | V.D. Natsik, L.S. Fomenko, S.V. Lubenets. | |
Summary: | | |
Keywords: | | |
Edition: | Fizika Tverdogo Tela | | | 2013,
940-952 ,Russian |
004 Saturation of the C60 hydrogen: a study of the adsorption of crossover |
Authors: | Yagotintsev K.A. , Legchenkova I.V., Y.E. Stetsenko, P.V. Zinoviev, V.N. Zoryansky, A.I. Prokhvatilov, M.A. Strzhemechny | |
Summary: | | |
Keywords: | | |
Edition: | Low Temperature Physics | | | 2012,
1202,Russian |
The events in the framework of the project |
004 004 004 004 004 004 004 004 004
|
004 1.1. Nanophysics: fundamental problems Purpose: Expected results:Issue of new types of products: methods, theories Stage 1: Stage 2: Stage 3: Stage 4: Stage 5:
|