• Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 
Low Temp Phys Banner

Flickr Twitter UniPHY Group iResearch App Facebook

SECTION LISTING

Search Issue | RSS Feeds RSS
Next Issue

Jan 2010

Volume 36, Issue 1, pp. 1-118


Vector matter

M. A. Obolenskiĭ

Low Temp. Phys. 36, 1 (2010); http://dx.doi.org/10.1063/1.3292285 (1 page)

Full Text: Read Online (HTML) | Download PDF

Abstract Unavailable
Show PACS
99.10.Np Editorial note
74.25.Uv Vortex phases (includes vortex lattices, vortex liquids, and vortex glasses)

Ideal and distorted vortex lattice in bulk and film superconductors (Review)

Ernst Helmut Brandt

Low Temp. Phys. 36, 2 (2010); http://dx.doi.org/10.1063/1.3293696 (11 pages) | Cited 2 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The solution of the linearized Ginzburg-Landau theory describing a periodic lattice of vortex lines in type-II superconductors with high inductions and first discovered by Abrikosov is generalized to nonperiodic vortex arrangements, e.g. lattices with a vacancy, surrounded by a relaxing vortex lattice, and periodically distorted lattices that are needed in the nonlocal theory of elasticity of a vortex lattice. Generalizations to lower magnetic inductions and three-dimensional arrangements of curved vortex lines are also given. It is shown how a periodic vortex lattice can be computed for bulk superconductors and for thick and thin films in a perpendicular field for all inductions B and all Ginzburg-Landau parameters κ.
Show PACS
74.70.-b Superconducting materials other than cuprates
74.25.Wx Vortex pinning (includes mechanisms and flux creep)
74.20.De Phenomenological theories (two-fluid, Ginzburg-Landau, etc.)
74.25.Ha Magnetic properties including vortex structures and related phenomena
74.25.Ld Mechanical and acoustical properties, elasticity, and ultrasonic attenuation
74.78.-w Superconducting films and low-dimensional structures

Critical states in thin planar type-II superconductors in a perpendicular or inclined magnetic field (Review)

G. P. Mikitik

Low Temp. Phys. 36, 13 (2010); http://dx.doi.org/10.1063/1.3292280 (26 pages) | Cited 1 time

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The theory of the critical states of a vortex lattice in type-II superconductors is examined without any assumptions about the relative perpendicularity of the local magnetic fields and circulating currents in the sample. Such a theory has made it possible to solve a number of problems for thin films of superconductors in an external magnetic field oriented perpendicular to their surface: a theory of the shaking effect is constructed for rectangular superconducting plates and the critical states in samples with anisotropic pinning of the flux lines as well as in the presence of an order-disorder phase transition in a vortex lattice are studied. In addition, the critical states in a long superconducting strip in an inclined magnetic field are investigated.
Show PACS
74.25.Wx Vortex pinning (includes mechanisms and flux creep)

Nonlinear electrodynamics of vortex matter in hard superconductors (Review)

I. F. Voloshin, L. M. Fisher, and V. A. Yampol’skiĭ

Low Temp. Phys. 36, 39 (2010); http://dx.doi.org/10.1063/1.3292283 (20 pages) | Cited 4 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Nontrivial electrodynamic properties of vortex matter, which are due to a specific nonlinearity of the material equations, in hard superconductors are discussed: collapse of the transport current and the static magnetization of superconductors by an external orthogonal ac magnetic field; appearance of jumps in the time dependence of the electric field at the boundary of a sample as a result of nonlinear interaction of waves having different frequencies; specific staged penetration of an electromagnetic field into anisotropic superconductors. Nonlocal effects resulting in a large modification of nonlinear phenomena are also examined. Special attention is given to a discussion of the unique phenomenon of macroturbulent instability, associated with the flow of Abrikosov vortices, in hard superconductors. Most results presented are based on original experimental and theoretical investigations performed with the participation of the present authors.
Show PACS
74.25.Wx Vortex pinning (includes mechanisms and flux creep)

HTSC cuprate films doped with nanoparticles and their electrodynamics, determined by Abrikosov vortices

V. S. Flis, A. A. Kalenyuk, A. L. Kasatkin, V. O. Moskalyuk, A. I. Rebikov, V. L. Svechnikov, K. G. Tret’yachenko, and V. M. Pan

Low Temp. Phys. 36, 59 (2010); http://dx.doi.org/10.1063/1.3292938 (12 pages)

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This paper presents the results of a comprehensive study of the relationship of the structural and electrodynamic characteristics of quasi-single-crystal films of the HTSC cuprate YBa2Cu3O7−δ (YBCO) with various concentrations (several mass percent) of nanosize inclusions of the perovskitelike phase of BaZrO3 (BZO). High-resolution electron microscopy is used to investigate the nanostructure of the fabricated films and to determine the main types of defects that cause strong pinning of Abrikosov vortices and, accordingly, large critical current densities. The results of theoretically modelling the genesis of the defect nanostructure that appears in such films and its influence on the critical current are presented. The magnetic and transport properties of HTSC films made from YBCO(BZO) have been experimentally studied. The temperature, magnetic-field, and magnetic-orientation dependences of the critical current density of the test films are found. The results of an experimental investigation of the high-frequency properties of YBZO(BZO) films—the surface microwave impedance of the films in the linear and nonlinear regimes—are also given. The experimental results are discussed, and the influence of the nanostructure of the impurity phase on the electrodynamic characteristics of the HTSC films is analyzed.

The Hall effect and microwave absorption by vortices in an anisotropic superconductor with a periodic pinning potential

V. A. Shklovskij and Dang Thi Bich Hop

Low Temp. Phys. 36, 71 (2010); http://dx.doi.org/10.1063/1.3292939 (10 pages)

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This paper presents the results of theoretical calculations of the absorbed power, the impedance tensors, and the magnetoresistances of anisotropic superconductors of the second kind in a model of a periodic pinning potential in the presence of the Hall effect.
Show PACS
74.25.fc Electric and thermal conductivity
74.25.Wx Vortex pinning (includes mechanisms and flux creep)

Features of the temperature dependence and magnetic-field dependence of the critical current density close to the critical temperature in YBa2Cu3O7−δ thin films

D. G. Kovalchuk, M. P. Chornomorets, S. M. Ryabchenko, E. A. Pashitskii, and A. V. Semenov

Low Temp. Phys. 36, 81 (2010); http://dx.doi.org/10.1063/1.3292940 (11 pages)

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The temperature dependence of the critical density of superconducting current jc(τ) [τ = (1−T/Tc), and Tc is the critical temperature] of two epitaxial c-oriented YBa2Cu3O7−δ thin films grown on LaAlO3 and SrTiO3 substrates has been investigated by the method of dynamic magnetic susceptibility. In both samples, the jc(τ) dependence has two sections with power dependences jc ∼ τ3/2 and jc ∼ τ2 in the temperature region from 77 K to Tc, with crossover between them. Measurements were made of the temperature dependences of the dynamic relaxation rate Q(τ) (magnetic flux creep), which turned out to be unconnected with the observed crossovers. It is shown that the observed features of jc(τ) are not caused, as was assumed earlier, by the limitation of the critical depairing current density in the interdislocation gaps of the interblock boundaries of YBa2Cu3O7−δ epitaxial thin films. Based on numerical calculations, it is shown that the existence of crossovers and the breakdown of H/τ scaling detected in one of the samples (H is the dc magnetic field) in the jc(τ,H) magnetic-field dependences close to Tc can be explained by the manifestation of macroscopic inhomogeneity of the samples in the local values of the critical temperature Tc (Tc inhomogeneity). The absence of observable breakdown of the H/τ scaling in the second sample is explained by the smaller width of the distribution over Tc in it by comparison with the first sample.
Show PACS
74.78.-w Superconducting films and low-dimensional structures
74.72.-h Cuprate superconductors
74.25.Sv Critical currents
74.25.Wx Vortex pinning (includes mechanisms and flux creep)
74.25.Uv Vortex phases (includes vortex lattices, vortex liquids, and vortex glasses)
74.25.Ha Magnetic properties including vortex structures and related phenomena

Hysteresis jumps of the surface reactance of a layered superconductor as the incident wave amplitude varies

S. S. Apostolov, D. V. Kadygrob, Z. A. Mayselis, T. M. Slipchenko, S. E. Savel’ev, and V. A. Yampol’skii

Low Temp. Phys. 36, 92 (2010); http://dx.doi.org/10.1063/1.3294429 (8 pages)

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The nonlinear response of a layered superconductor to symmetric (in magnetic field) electromagnetic excitation has been theoretically investigated. An ambiguous dependence of the phase of the reflected signal on the amplitude H0 of the irradiating wave is predicted. This causes hysteresis jumps in the dependence of the surface reactance of the superconductor on H0. If the frequency of the irradiating field is close to the Josephson plasma frequency, this unusual nonlinear effect can be observed when the amplitudes of the ac field are not very strong. The conditions for the appearance of hysteresis are obtained. Expressions for the phase shift of the reflected wave are derived, using the coupled sine-Gordon equations. Moreover, a class of solutions of these equations that are discontinuous in the coordinate are studied that correspond to a continuous spatial distribution of the magnetic field in the superconductor. Such solutions result in the appearance of additional branches in the dependence of the phase shift of the reflected wave on the incident wave amplitude.
Show PACS
74.25.N- Response to electromagnetic fields
74.78.Fk Multilayers, superlattices, heterostructures
74.50.+r Tunneling phenomena; Josephson effects

Experience in numerically modelling the mixed state of superconductors, applied to a study of the nonstationary Schrödinger equation

A. E. Filippov

Low Temp. Phys. 36, 100 (2010); http://dx.doi.org/10.1063/1.3294430 (5 pages)

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Experience in numerically modelling superconducting systems has been used to investigate the behavior of a nonstationary wave function far from equilibrium. It is shown that normalization of the wave function plays the role of an efficient nonlocal interaction that causes the wave function to be localized in one of the wells even for an infinitesimal difference of their depths. This fundamentally differs from the solution of the Fokker-Planck equation, which in equilibrium depends exponentially on the energy and is virtually symmetrical for wells that are similar in depth. When a fluctuational (small) variation causes the relative depths to reverse, the wave function’s maximum tunnels to the other well. A transition in a one-well potential from an excited state to a lower state is also considered. It is shown that this is accompanied by the emission of a localized segment of an electromagnetic wave, which can be identified with a “photon.”
Show PACS
74.25.Op Mixed states, critical fields, and surface sheaths
74.70.-b Superconducting materials other than cuprates

Static and dynamic order-disorder transition of a vortex lattice in YBaCuO crystals: The effect of point defects, anisotropy, temperature, and magnetic field

Yu. T. Petrusenko

Low Temp. Phys. 36, 105 (2010); http://dx.doi.org/10.1063/1.3294477 (5 pages)

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This paper presents the results of measurements of the field dependence Fp(H) and angle dependence Fp(α) of the pinning force in an YBa2Cu3O7−δ crystal that contains various concentrations of point defects. A comparison of the Fp(H) and Fp(α) dependences gives decisive reasons for assuming that, when the vortices travel at low velocities υ, the minimum on the Fp(α) dependence corresponds to the order-disorder transition in the vortex lattice (VL). It is shown that the minimum on the Fp(α) dependence shifts toward larger angles α at large velocities υ, and this is caused by the partial dynamic ordering of the disordered VL.
Show PACS
74.25.Uv Vortex phases (includes vortex lattices, vortex liquids, and vortex glasses)
61.72.J- Point defects and defect clusters
74.72.-h Cuprate superconductors
74.25.Wx Vortex pinning (includes mechanisms and flux creep)

The displacement and annihilation of macroscopic regions with hypervortices in ceramic YBa2Cu3O7−x

A. A. Shablo, V. P. Koverya, and S. I. Bondarenko

Low Temp. Phys. 36, 110 (2010); http://dx.doi.org/10.1063/1.3294478 (5 pages)

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Features of the controllable displacement, annihilation, and transformation of macroscopic regions of a weak frozen magnetic field (FMF) have been experimentally studied in a plate of granulated ceramic YBa2Cu3O7−x under the action of the transport current flowing through it. It is shown that the displacement of regions with an FMF lower than the first critical field of the ceramic granules (Hc1g) is associated with a relatively weak pinning force of the hypervortices that is less than the maximum experimentally attainable Lorenz force. A discussion is presented of the role of the transport current that not only is one of the conditions for the appearance of the Lorenz force but also acts on the internal current structure of the local FMF, which in turn influences its mobility and magnitude. If a local field greater than Hc1g is frozen in, the experimentally produced Lorenz force is less than the pinning force of the Abrikosov vortices in the mixed state of the granules, and there is no displacement of the regions with an FMF.
Show PACS
74.25.Wx Vortex pinning (includes mechanisms and flux creep)
74.72.-h Cuprate superconductors
back to top
RSS Feeds

Magnetoresistance and 2D-3D crossover in aluminum-doped YBa2Cu3−zAlzO7−δ single crystals with a system of unidirectional twinning boundaries

A. A. Zavgorodniĭ, R. V. Vovk, M. A. Obolenskiĭ, and A. V. Samoĭlov

Low Temp. Phys. 36, 115 (2010); http://dx.doi.org/10.1063/1.3292281 (4 pages) | Cited 1 time

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effect of a constant magnetic field to 12.7 kOe on the temperature dependences of the electric conductivity of aluminum-doped YBaCuO single crystals with a system of unidirectional twinning boundaries is investigated. The temperature dependences of the excess paraconductivity and the field dependence of the coherence length ξc(0,H) along the c axis are determined in the basal ab plane. It is determined that the twinning boundaries are effective centers of scattering of fluctuation carriers. The temperature dependences of the excess paraconductivity are interpreted on the basis of the Hikami-Larkin theoretical model of fluctuation conductivity for layered superconducting systems. The reasons for the suppression of three-dimensional superconducting fluctuations and the nonmonotonic dependence of ξc(0,H) in weak magnetic fields with the magnetic field vector oriented along the c axis are discussed.
Show PACS
74.25.fc Electric and thermal conductivity
74.25.Ha Magnetic properties including vortex structures and related phenomena
61.72.Mm Grain and twin boundaries
74.72.-h Cuprate superconductors
74.40.-n Fluctuation phenomena
Close
ADVERTISEMENT

Your Recent History Recent History Help

Recently Viewed

  1. The effect of the noncentral impurity–matrix interaction upon the thermal expansion and polyamorphism of CO–C60 solid solutions at low temperatures
  2. On a possible reason behind the anisotropy observed in the superconducting properties of underdoped cuprates
  3. Determination of low-energy electronic levels of the Tm3+ ion in the compound KTm(MoO4)2
Go to AIP Home
Copyright © American Institute of Physics
close