scholarly journals LOWER CRITICAL MAGNETIC FIELD OF SUPERCONDUCTING Rb3C60

1992 ◽  
Vol 06 (16n17) ◽  
pp. 1037-1042 ◽  
Author(s):  
V. BUNTAR ◽  
U. ECKERN ◽  
C. POLITIS
Keyword(s):  
Magnetic Field ◽  
Penetration Depth ◽  
High Field ◽  
Model Analysis ◽  
Critical Magnetic Field ◽  
Field Analysis ◽  
Zero Temperature ◽  
Bean Model ◽  
Good Agreement

The lower critical magnetic field Hc1 of superconducting Rb 3 C 60 (Tc=28.5 K ) is estimated by different methods. The zero temperature value is found to be given by Hc1=16.2±1.0 mT, and the penetration depth is λL=215±10 nm . The Bean model analysis leads to threshold fields of 5.3 mT for T=5 K , and 4.0 mT for T=17 K . The big influence of intergranular connections on Hc1 is demonstrated. Good agreement between the low- and the high-field analysis is found.

Superconductors with spin–orbit interactions

2016 ◽  
Vol 30 (25) ◽  
pp. 1650183 ◽  
Author(s):  
Yu. N. Ovchinnikov
Keyword(s):  
Magnetic Field ◽  
Superconducting Films ◽  
Critical Magnetic Field ◽  
Spin Orbit ◽  
Zero Temperature ◽  
Interband Pairing ◽  
Two Parameters ◽  
Spin Orbit Interactions ◽  
Parameter Values ◽  
Thin Superconducting Films

The effect of spin-orbit (SO) interaction on the formation of the critical states in thin superconducting films in magnetic field oriented along the film is investigated. Hereby, the case of interband pairing is considered. It was found that eight branches exist in the plane of two parameters [Formula: see text] determined by the value of magnetic field and SO interaction. Six modes leads to inhomogeneous states with different values of the impulse [Formula: see text]. Each state is doubly degenerate over direction of impulse [Formula: see text]. The parameter values at critical point are found for all eight branches in explicit form for zero temperature. The optimal two branches are estimated, corresponding to largest critical magnetic field value for given SO interaction.

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.

Degeneracy of antiferromagnetic Ising lattices at critical magnetic field and zero temperature

1978 ◽  
Vol 18 (5) ◽  
pp. 2304-2307 ◽  
Author(s):  
B. D. Metcalf ◽  
C. P. Yang
Keyword(s):  
Magnetic Field ◽  
Critical Magnetic Field ◽  
Zero Temperature ◽  
Ising Lattices

MAGNETIZATION STUDIES OF Rb3C60 IN SUPERCONDUCTING STATE

1993 ◽  
Vol 07 (11) ◽  
pp. 2163-2176 ◽  
Author(s):  
C. POLITIS ◽  
V. BUNTAR ◽  
V.P. SEMINOZHENKO
Keyword(s):  
Magnetic Field ◽  
Temperature Dependence ◽  
Critical Current ◽  
Magnetic Measurements ◽  
Landau Theory ◽  
Critical Magnetic Field ◽  
Zero Temperature ◽  
Ginzburg Landau ◽  
Different Temperatures ◽  
Increasing Temperature

We present the results of magnetic measurements in fields up to 50 kOe for superconducting Rb 3 C 60. The temperature dependence of upper H c 2 critical magnetic field is determined, from which the zero temperature value Hc2(0)=465±50 kOe is evaluated. The magnitudes of penetration depth and coherence length are calculated as ξ(0)=26.7±3 Å; λ L (0)=2150±100 Å at zero temperature. The temperature dependence of ξ(T) and λ L (T) for T≧23 K is in good agreement with the Ginzburg-Landau theory. The critical current densities for different temperatures are calculated, showing a strong decrease of Jc with increasing temperature for T≤7 K . Two regions of fading critical current density on a magnetic field dependence are found.

scholarly journals Electron transport, penetration depth, and the upper critical magnetic field in ZrB12 and MgB2

2005 ◽  
Vol 101 (1) ◽  
pp. 98-106 ◽  
Author(s):  
V. A. Gasparov ◽  
N. S. Sidorov ◽  
I. I. Zver’kova ◽  
S. S. Khassanov ◽  
M. P. Kulakov
Keyword(s):  
Magnetic Field ◽  
Electron Transport ◽  
Penetration Depth ◽  
Critical Magnetic Field ◽  
Upper Critical Magnetic Field

scholarly journals ANALYTICAL STUDY OF CRITICAL MAGNETIC FIELD IN A HOLOGRAPHIC SUPERCONDUCTOR

2013 ◽  
Vol 28 (08) ◽  
pp. 1350024 ◽  
Author(s):  
D. MOMENI ◽  
EIJI NAKANO ◽  
M. R. SETARE ◽  
WEN-YU WEN
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Critical Temperature ◽  
General Feature ◽  
Analytical Study ◽  
Critical Magnetic Field ◽  
Zero Temperature ◽  
Holographic Superconductor ◽  
Holographic Superconductors ◽  
Sturm Liouville

We analytically study the effect of magnetic field in a holographic superconductor by using Sturm–Liouville method. We estimate the coefficient of proportionality at critical temperature and find its dependence on bulk magnetic field. By exploring the phase diagrams of critical temperature and magnetic field for various condensates, we conclude that the existence of critical magnetic field is a general feature in holographic superconductors. We also study the quantum phase transition at zero temperature and find that the critical charge density increases linearly with the condensate dimension.

London Penetration Depth of Fe-Based Superconductors

2014 ◽  
Vol 979 ◽  
pp. 297-301 ◽  
Author(s):  
Arpapong Changjan ◽  
Pongkaew Udomsamuthirun
Keyword(s):  
Magnetic Field ◽  
Free Energy ◽  
Penetration Depth ◽  
Electrical Resistance ◽  
Critical Magnetic Field ◽  
London Penetration Depth ◽  
Iron Compounds ◽  
Ginzburg Landau ◽  
The Magnetic Field ◽  
Very High

Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in certain materials when cooled below a characteristic critical temperature. Fe-based superconductors are superconductors whose containing iron compounds and having a very high critical magnetic field. London penetration depth can assist in the study of the behavior of the critical magnetic field. The London penetration depth is the distance to which a magnetic field penetrates into a superconductor and becomes equal to 0.367879 times that of the magnetic field at the surface of the superconductor. In this paper, the London penetration depth of Fe-based superconductors is studied by Ginzburg-Landau scenery. Free energy of Fe-based superconductors is assumed by modified the free energy of two-band magnetic superconductors model and theof Fe-based superconductors is derived analytically. Finally, the temperature dependence of is investigated and applied to Single-Crystal superconductors.

Critical magnetic-field angle for high-field current transport in YBa2Cu3O7 at 76 K

Cryogenics ◽  
1992 ◽  
Vol 32 (11) ◽  
pp. 1089-1091 ◽  
Author(s):  
J.W. Ekin
Keyword(s):  
Magnetic Field ◽  
High Field ◽  
Critical Magnetic Field ◽  
Current Transport

Functional derivatives for the critical magnetic field of Pb

1978 ◽  
Vol 56 (9) ◽  
pp. 1248-1254 ◽  
Author(s):  
J. M. Daams ◽  
J. P. Carbotte
Keyword(s):  
Magnetic Field ◽  
Critical Temperature ◽  
Critical Field ◽  
Coulomb Repulsion ◽  
Critical Magnetic Field ◽  
Deviation Function ◽  
Functional Derivatives ◽  
First Time ◽  
Reduced Temperature ◽  
Good Agreement

We have calculated for superconducting Pb in the dirty (isotropic) limit the following functional derivatives: δTc/δα2F(ω), δHc(0)/δα2F(ω), δD(t)/δα2F(ω), ∂Tc/∂μ*, ∂Hc(0)/∂μ*, and ∂D(t)/∂μ*, where Tc, Hc(0), D(t), t, α2(ω)F(ω), and μ* are, respectively, the critical temperature, critical field at T = 0, deviation function for the critical field, reduced temperature T/Tc, electron–phonon spectral density, and Coulomb repulsion parameter. Our values for the first two functional derivatives are in good agreement with previous work by Rainer and Bergmann. We present the others here for the first time to relate the observed changes in Tc, Hc(0), and D(t) under hydrostatic pressure to the change in α2(ω)F(ω) and μ*.

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