scholarly journals Cutoff parameter versus Ginzburg-Landau coherence length in the mixed state of high-κ superconductors with impurities: quasiclassical approach

2012 ◽  
Vol 400 (2) ◽  
pp. 022007
Author(s):  
P Belova ◽  
I Zakharchuk ◽  
K B Traito ◽  
E Lähderanta
Keyword(s):  
Mixed State ◽  
Coherence Length ◽  
Ginzburg Landau ◽  
Cutoff Parameter ◽  
Parameter Versus

scholarly journals Theoretical Study of Upper Critical Magnetic Field (HC2) in Multiband Iron Based Superconductors

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Tsadik Kidanemariam ◽  
Gebregziabher Kahsay
Keyword(s):  
Magnetic Field ◽  
Phase Diagrams ◽  
Penetration Depth ◽  
Coherence Length ◽  
Symmetry Axis ◽  
Critical Magnetic Field ◽  
Ginzburg Landau ◽  
Iron Based Superconductors ◽  
Upper Critical Magnetic Field ◽  
Iron Based

This research work focuses on the theoretical investigation of the upper critical magnetic field,HC2; Ginzburg-Landau coherence length,ξGL(T); and Ginzburg-Landau penetration depth,λGL(T), for the two-band iron based superconductorsBaFe2(As1-xPx)2,NdO1-xFxFeAs, and LiFeAs. By employing the phenomenological Ginzburg-Landau (GL) equation for the two-band superconductorsBaFe2(As1-xPx)2,NdO1-xFxFeAs, and LiFeAs, we obtained expressions for the upper critical magnetic field,HC2; GL coherence length,ξGL; and GL penetration depth,λGL, as a function of temperature and the angular dependency of upper critical magnetic field. By using the experimental values in the obtained expressions, phase diagrams of the upper critical magnetic field parallel,HC2∥c, and perpendicular,HC2⊥c, to the symmetry axis (c-direction) versus temperature are plotted. We also plotted the phase diagrams of the upper critical magnetic field,HC2versus the angleθ. Similarly, the phase diagrams of the GL coherence length,ξGL, and GL penetration depth,λGL, parallel and perpendicular to the symmetry axis versus temperature are drawn for the superconductors mentioned above. Our findings are in agreement with experimental observations.

scholarly journals Coherence length of magnetic field in the mixed state of type-II superconductors

2011 ◽  
Vol 303 ◽  
pp. 012114
Author(s):  
P Belova ◽  
M Safonchik ◽  
K B Traito ◽  
E Lähderanta
Keyword(s):  
Magnetic Field ◽  
Mixed State ◽  
Coherence Length ◽  
Type Ii ◽  
Type Ii Superconductors

TRANSPORT PHENOMENA IN THE MIXED STATE AND FLUCTUATION REGIME IN (Bi1.6Pb0.4)Sr2Ca1-xHox(Cu1-yZny)2O8+d

2001 ◽  
Vol 15 (21) ◽  
pp. 929-934
Author(s):  
G. ILONCA ◽  
A. V. POP ◽  
R. STIUFIUC ◽  
G. STIUFIUC ◽  
C. LUNG ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Mixed State ◽  
Landau Theory ◽  
Hole Concentration ◽  
Transport Coefficients ◽  
Time Dependent ◽  
Ginzburg Landau ◽  
Metallic Behavior ◽  
Fluctuation Effects ◽  
Longitudinal Resistivity

Measurements of the magnetoresistivity, Seebeck, Nernst and Hall coefficients in Bi:2212 superconductors doped with Ho and Zn are reported. The critical temperature and the transport coefficients depend strongly on the Ho and Zn contents. The tails of the transport coefficients versus temperature curves are caused by fluctuation effects, which increase with increasing magnetic field. An anomalous suppression of superconductivity at x = 0.25–0.35 and y = 0.025–0.032 was also found when the hole concentration per Cu is P H = 1/8 and the transport properties exhibit metallic behavior. It was found that dB c2 /dT = -2.4 ± 0.2 T/K , corresponding to a Ginzburg–Landau coherence length ξ = 15 Å. The Hall resistivity ρxy scaling with the longitudinal resistivity ρxx as [Formula: see text] with α ≈ 1.8 is in agreement with the theory of Vinokur et al. The experimental data in the mixed state are in agreement with the prediction of the time-dependent Ginzburg–Landau theory.

SCALING BETWEEN LOCALIZATION LENGTH AND TC IN DISORDERED YBa2Cu3O6.9

1999 ◽  
Vol 13 (29n31) ◽  
pp. 3601-3604
Author(s):  
ANDREA GAUZZI ◽  
DAVOR PAVUNA
Keyword(s):  
Coherence Length ◽  
Localization Length ◽  
Charge Carriers ◽  
Superconducting Transition ◽  
Scaling Relation ◽  
X Ray Diffraction ◽  
Ginzburg Landau ◽  
X Ray ◽  
Structural Coherence ◽  
Superconducting Coherence Length

We quantitatively study the effect of growth-induced reduction of long range structural order on the superconducting transition in epitaxial YBa 2 Cu 3 O 6.9 films. The corresponding reduction of structural coherence length rc is determined from the width of X-ray diffraction rocking curves. Tc measurements in the films give evidence for the validity of the empirical scaling relation ΔTc~ rc,ab-2, where ΔTc is the disorder-induced reduction of Tc and rc,ab is the structural coherence length in the ab-plane. To explain this algebraic law we propose a simple phenomenological model based on the disorder-induced localization of the charge carriers within each ordered domain of size rc,ab. This picture enables us to precisely determine the Ginzburg-Landau superconducting coherence length in the ab-plane, and we obtain ξab=1.41±0.04 nm.

scholarly journals Зависимость критической температуры цилиндрических сверхпроводников от граничных условий

2020 ◽  
Vol 62 (10) ◽  
pp. 1594
Author(s):  
А.Н. Лыков
Keyword(s):  
Boundary Conditions ◽  
Coherence Length ◽  
Order Parameter ◽  
Landau Theory ◽  
Small Diameter ◽  
Superconducting Order Parameter ◽  
Superconducting Properties ◽  
Ginzburg Landau

The paper presents the results of a study of the properties of long cylindrical superconductors with a diameter of the order of coherence length ξ, performed in the framework of the Ginzburg-Landau theory (GL). Boundary conditions of general form are used for solution of the GL equa-tion for superconducting order parameter. Using such boundary conditions allows us to take into account the influence of the cylinder boundary on its superconducting properties. This ap-proach is important for small-diameter cylinders, whose properties significantly depend on the properties of their boundaries.

TRANSPORT PHENOMENA IN THE MIXED STATE OF (Bi1.6Pb0.4) Sr2Ca2 (Cu1-xGax)3Oy BULK MATERIALS

2001 ◽  
Vol 15 (23) ◽  
pp. 1041-1046
Author(s):  
G. ILONCA ◽  
A. V. POP ◽  
G. STIUFIUC ◽  
R. STIUFIUC ◽  
C. LUNG
Keyword(s):  
Mixed State ◽  
Landau Theory ◽  
Solid State Reaction Method ◽  
Power Coefficient ◽  
Bulk Materials ◽  
Critical Temperatures ◽  
Conventional Solid State Reaction ◽  
Ginzburg Landau ◽  
Seebeck Coefficients ◽  
Hall Effects

We have performed a study of magnetoresistivity, Seebeck, Nernst and Hall effects in the mixed state and in the fluctuation regime above T c 0 for Bi:2223 bulk doped with Ga (0 ≤ x ≤ 0.05), prepared by the conventional solid state reaction method, in magnetic fields between 0 and 5 T and in the temperature range 5–120 K. It was found that critical temperatures, the Hall concentration, and the Nernst and Seebeck coefficients depend strongly on the Ga contents in the samples. The Hall resistivity ρxy showed a sign anomaly in the mixed state and scaled with longitudinal resistivity ρxx with a power coefficient β ≅ 2. The experimental data are in agreement with the predictions of the time-dependent Ginzburg–Landau theory.

PENETRATION DEPTH AND COHERENCE LENGTH IN SUPERCONDUCTING FULLERENE Rb3C60

1992 ◽  
Vol 06 (06) ◽  
pp. 351-357 ◽  
Author(s):  
C. POLITIS ◽  
A.I. SOKOLOV ◽  
V. BUNTAR
Keyword(s):  
Penetration Depth ◽  
Coherence Length ◽  
High Field ◽  
Field Data ◽  
Diamagnetic Susceptibility ◽  
Magnetic Measurements ◽  
Ginzburg Landau ◽  
Order Of Magnitude

The penetration depth λ and the coherence length ξ in Rb 3 C 60 fullerene are determined by means of magnetic measurements in fields up to 50 kOe. For the Ginzburg-Landau coherence length the estimate ξ GL (0)=23 Å is obtained, while the magnitude of λ GL (0) extracted from the high-field data turns out to lie between 1200 and 1400 Å, with the upper value being more likely. Non-superconducting diamagnetic susceptibility is also measured and found to be equal to −(0.60±0.02)×10−5 which is an order of magnitude higher than that of undoped fullerene.

Duality and color confinement in restricted gauge theory

2000 ◽  
Vol 77 (10) ◽  
pp. 795-811
Author(s):  
JMS Rana
Keyword(s):  
Gauge Theory ◽  
Quantum Chromodynamics ◽  
Coherence Length ◽  
Landau Theory ◽  
London Penetration Depth ◽  
Ginzburg Landau ◽  
Energy Functions ◽  
Color Confinement ◽  
Vortex Solutions ◽  
Flux Energy

Using electromagnetic duality, the isocolor charge-dyon interactions were studied in restricted quantum chromodynamics (RCD) in terms of current-current correlations in the magnetic gauge using the dielectric and permeability parameters of the associated vacuum. The resulting 1/k4 behaviour of the dual propagators is interpreted as a signature of confinement for the corresponding colored fluxes of the theory. Evaluating the vortex solutions of RCD semi-quantitatively, in accordance with Higgs-Ginzburg-Landau theory, expressions for London penetration depth, coherence length, and associated flux energy functions for types I and II superconducting media are derived and an analogy of the type of superconducting medium with the bag model and string picture of hadrons is discussed.PACS Nos.: 11.30 Jw, 14.80 Hv, 12.38 Aw

IMPACT OF THE ORDER PARAMETER SYMMETRIES ON THE VORTEX CORE STRUCTURE IN IRON-BASED SUPERCONDUCTORS

2012 ◽  
Vol 26 (21) ◽  
pp. 1230013
Author(s):  
POLINA BELOVA ◽  
IVAN ZAKHARCHUK ◽  
KONSTANTIN BORISOVICH TRAITO ◽  
ERKKI LÄHDERANTA
Keyword(s):  
Fermi Surface ◽  
Mixed State ◽  
Order Parameter ◽  
Spin Fluctuation ◽  
Pairing Symmetry ◽  
Gap Function ◽  
Spin Fluctuations ◽  
Field Range ◽  
Cutoff Parameter ◽  
Antiferromagnetic Spin

Effects of the order parameter symmetries on the cutoff parameter ξh (determining the magnetic field distribution) in the mixed state are investigated in the framework of quasiclassical Eilenberger theory for isotropic s±, s++ and anisotropic dx2-y2-wave superconducting pairings. These symmetries are proposed for the pairing state of the Fe -pnictides. In s± pairing symmetry, the gap function has opposite sign at the electron and hole pockets of the Fermi surface, it is connected with interband antiferromagnetic spin fluctuations. In s++ pairing symmetry, the gap function has the same sign at the Fermi surface, it is mediated by moderate electron–phonon interaction due to Fe -ion oscillation and the critical orbital fluctuation. The dx2-y2 pairing symmetry can rise from intraband antiferromagnetic spin fluctuation in strongly hole overdoped iron pnictide KFe 2 As 2 and ternary chalcogenides. The s± pairing symmetry results in different effects of intraband (Γ0) and interband (Γπ) impurity scattering on ξh. It is found that ξh/ξc2 value decreases with Γ0 leading to the values much less than those predicted by the analytical Ginzburg–Landau (AGL) theory for high Γ0. At very high Γ0, the interband scattering suppresses ξh/ξc2 considerably below one in the whole field range making it flat for both s± and s++ pairing symmetries. Scaling of the cutoff parameter with the electromagnetic coherence length shows the importance of the nonlocal effects in mixed state. The small values of ξh/ξc2 were observed in μSR measurements of Co -doped BaFe 2 As 2. If Γ0 and Γπ are small and equal than the ξh/ξc2(B/Bc2) dependence for s± symmetry behaves like that of the AGL model and shows a minimum with value much more than that obtained for s++ superconductors. With high Γπ, the ξh/ξc2(B/Bc2) dependence resides above the AGL curve for s± pairing symmetry, as observed in SANS measurements of stoichiometrical LiFeAs compound. In d-wave superconductors, ξh/ξc2 always increases with Γ similar to the s± symmetry case with Γ0 = Γπ.

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