Temperature dependence of the anisotropy parameter of the LiFeAs upper critical field in the two-band Ginzburg-Landau theory

2013 ◽  
Vol 58 (6) ◽  
pp. 888-891 ◽  
Author(s):  
I. N. Askerzade ◽  
N. Guclu ◽  
R. T. Tagiyeva
Keyword(s):  
Temperature Dependence ◽  
Critical Field ◽  
Landau Theory ◽  
Anisotropy Parameter ◽  
Upper Critical Field ◽  
Ginzburg Landau

THE TWO-BAND GINZBURG–LANDAU THEORY ANALYSIS ON THE UPPER CRITICAL FIELD OF Mg1-xAlxB2

2011 ◽  
Vol 25 (22) ◽  
pp. 3035-3042
Author(s):  
MINXIA LIU ◽  
JIANWEN AI ◽  
GUIHUA CHEN ◽  
YONGZHAO XU ◽  
XIDUO HU
Keyword(s):  
Experimental Data ◽  
Temperature Dependence ◽  
Single Crystals ◽  
Critical Field ◽  
Landau Theory ◽  
Upper Critical Field ◽  
Broad Temperature Range ◽  
Anisotropy Ratio ◽  
Theory Analysis ◽  
Ginzburg Landau

We studied the temperature dependence of the upper critical field Hc2(T) of Mg 1-x Al x B 2 single crystals (x=0.024 and 0.092) using the two-band Ginzburg–Landau theory. We found that this theory can describe Hc2(T) very well in the broad temperature range. The values of the parameters obtained by fitting experimental data to the theory indicated that the anisotropy of the σ bands decreased with the Al concentration. Accordingly, the temperature dependence of the anisotropy ratio of Hc2(γH) systematically decreased, and for x=0.092, γH was nearly independent of temperature.

Ginzburg–Landau theory of the Abrikosov vortex state near the upper critical field

1982 ◽  
Vol 60 (3) ◽  
pp. 299-303 ◽  
Author(s):  
A. E. Jacobs
Keyword(s):  
Critical Field ◽  
Landau Theory ◽  
Upper Critical Field ◽  
Vortex State ◽  
Quantization Condition ◽  
Abrikosov Vortex ◽  
Ginzburg Landau ◽  
Type Ii Superconductors ◽  
Flux Quantization ◽  
The Magnetic Field

A method which preserves the flux-quantization condition in all orders of perturbation theory is applied to the Ginzburg–Landau theory of type-II superconductors near the upper critical field. Expansions are obtained for the order parameter, the magnetic field, and the free energy; previous results are verified and extended to one higher order in Hc2 – Ha.

Mean-field analysis on the magnetic properties of non-centrosymmetric superconductor LaNiC2

2018 ◽  
Vol 96 (2) ◽  
pp. 189-193
Author(s):  
Jia-Li Zhang
Keyword(s):  
Critical Field ◽  
Landau Theory ◽  
Theoretical Calculations ◽  
Mean Field ◽  
Upper Critical Field ◽  
Field Analysis ◽  
S Wave ◽  
Wave State ◽  
Ginzburg Landau ◽  
Upward Curvature

Based on two-band isotropic Ginzburg–Landau theory, we study the temperature dependence of upper critical field and London penetration depth for non-centrosymmetric superconductor LaNiC2. All the theoretical calculations fit the experimental data very well, especially the upward curvature of upper critical field near the critical temperature. Our results thus indicate that the two-gap scenario is better to account for the superconductivity of LaNiC2, and the Cooper pairs of this superconductor are in the conventional s-wave state.

Ginzburg–Landau Theory for Two-Band Isotropic s-Wave Superconductors

2003 ◽  
Vol 17 (16) ◽  
pp. 3001-3020 ◽  
Author(s):  
I. N. Askerzade
Keyword(s):  
Magnetic Field ◽  
Critical Field ◽  
Landau Theory ◽  
Upper Critical Field ◽  
Single Band ◽  
S Wave ◽  
Ginzburg Landau ◽  
Surface Magnetic Field ◽  
Specific Heat Jump ◽  
Gl Theory

Temperature dependence of the upper critical field Hc2(T), lower critical field Hc1(T) and thermodynamic magnetic field Hcm(T) are studied in the vicinity of Tc using a two-band Ginzburg–Landau (GL) theory. The results are shown to be in a good agreement with experimental data for the superconducting magnesium diboride (MgB2) and non-magnetic borocarbides LuNi 2 B 2 C ( YNi 2 B 2 C ). In addition, two-band GL theory was applied for the calculation of specific heat jump, which is smaller than in single-band GL theory. Peculiarities of Little–Parks effect in two-band GL theory are studied also. It is shown that the quantization of the magnetic flux and the relation between surface magnetic field Hc3(T) and upper critical field Hc2(T) are the same as in single band GL theory.

THE UPPER CRITICAL FIELD OF THIN FILMS OF TWO-BAND SUPERCONDUCTORS: AN APPLICATION TO MgB2

2004 ◽  
Vol 18 (30) ◽  
pp. 1525-1531 ◽  
Author(s):  
I. N. ASKERZADE
Keyword(s):  
Experimental Data ◽  
Thin Films ◽  
Temperature Dependence ◽  
Critical Field ◽  
Qualitative Agreement ◽  
Magnesium Diboride ◽  
Upper Critical Field ◽  
Ginzburg Landau

Temperature dependence of the upper critical field [Formula: see text] of thin films of two-band superconductors is studied using the two-band Ginzburg–Landau (G–L) theory. The results are shown to be in qualitative agreement with experimental data for the superconducting magnesium diboride MgB 2 films.

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