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.

The Upper Critical Magnetic Field of Superconducting YBa2(Cu1-xNix)3O7

1989 ◽  
Vol 169 ◽  
Author(s):  
Youwen Xu ◽  
A. R. Moodenbaugh ◽  
M. Suenaga
Keyword(s):  
Magnetic Field ◽  
Specific Heat ◽  
Penetration Depth ◽  
Coherence Length ◽  
Critical Magnetic Field ◽  
Upper Critical Magnetic Field ◽  
Ni Content ◽  
Landau Parameter ◽  
Superconducting Coherence Length

AbstractThe upper critical magnetic field of a series samples of YBa2(Cu1-xNix)3O7 is measured. Other related parameters, such as the lower critical magnetic field Hc1, the Ginsberg-Landau parameter k, the jump in the specific heat ∆C/Tc, the superconducting coherence length ξ, and the penetration depth λ, are calculated from Tc, dHc2/dT and dM/dH. The results show that Hc2(0), and consequently ξ(0), are essentially constant, but Hc and ∆C/Tc decrease with increasing Ni content.

scholarly journals Quantum oscillations and upper critical magnetic field of the iron-based superconductor FeSe

2015 ◽  
Vol 109 (2) ◽  
pp. 27003 ◽  
Author(s):  
Alain Audouard ◽  
Fabienne Duc ◽  
Loïc Drigo ◽  
Pierre Toulemonde ◽  
Sandra Karlsson ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Critical Magnetic Field ◽  
Quantum Oscillations ◽  
Upper Critical Magnetic Field ◽  
Iron Based

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

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.

Superconducting Fluctuations Above TC and the Uncertainty Principle: How Small may the Coherence Length be?

2003 ◽  
Vol 17 (18n20) ◽  
pp. 3470-3472 ◽  
Author(s):  
F. Vidal ◽  
M. V. Ramallo ◽  
J. Mosqueira ◽  
C. Carballeira
Keyword(s):  
Magnetic Field ◽  
Wave Function ◽  
Uncertainty Principle ◽  
Coherence Length ◽  
Critical Magnetic Field ◽  
Field Amplitude ◽  
Cooper Pairs ◽  
Upper Critical Magnetic Field ◽  
Fluctuation Effects ◽  
Superconducting Fluctuations

We summarize here some of our recent results on the superconducting fluctuation effects above TC in different low- and high-TC superconductors, at high reduced-temperatures and magnetic fields. These results confirm our proposal that the collective behaviour of the fluctuating Cooper pairs in the short-wavelength fluctuation regime is dominated by the uncertainty principle, which imposes a limit to the shrinkage of the superconducting wave function when T increases well above TC or H becomes of the order of Hc2(0), the upper critical magnetic field amplitude extrapolated to T = 0 K .

scholarly journals A holographic model of d-wave superconductor vortices with Lifshitz scaling

2016 ◽  
Vol 25 (02) ◽  
pp. 1650021 ◽  
Author(s):  
Hong Guo ◽  
Fu-Wen Shu ◽  
Jing-He Chen ◽  
Hui Li ◽  
Ze Yu
Keyword(s):  
Magnetic Field ◽  
Vortex Lattice ◽  
Critical Magnetic Field ◽  
Ginzburg Landau ◽  
Vortex Lattices ◽  
Upper Critical Magnetic Field ◽  
Holographic Superconductors ◽  
Superconducting Coherence Length ◽  
Higher Order Corrections ◽  
Gl Theory

We study analytically the [Formula: see text]-wave holographic superconductors with Lifshitz scaling in the presence of external magnetic field. The vortex lattice solutions of the model have also been obtained with different Lifshitz scaling. Our results imply that holographic [Formula: see text]-wave superconductor is indeed a type II one even for different Lifshitz scaling. This is the same as the conventional [Formula: see text]-wave superconductors in the Ginzburg–Landau (GL) theory. Our results also indicates that the dynamical exponent [Formula: see text] cannot affect the droplet solutions, and the vortex lattice solutions receive its effects only in the radial part. This naively implies that it does not have direct influence on the shape of vortex lattice even after the higher-order corrections are taken into consideration (away from the phase transition point [Formula: see text]). However, it has effects on the upper critical magnetic field [Formula: see text] through the fact that a larger [Formula: see text] results in a smaller [Formula: see text] and therefore influences the size (characterized by [Formula: see text]) of the vortex lattices. Furthermore, close comparisons between our results and those of the GL theory reveal the fact that the upper critical magnetic field [Formula: see text] is inversely proportional to the square of the superconducting coherence length [Formula: see text], regardless of the anisotropy between space and time.

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