Nucleation of superconductivity in decreasing fields. I

1994 ◽  
Vol 5 (4) ◽  
pp. 449-468 ◽  
Author(s):  
S. J. Chapman
Keyword(s):  
Magnetic Field ◽  
Perturbation Theory ◽  
External Magnetic Field ◽  
Superconducting State ◽  
Landau Theory ◽  
Ginzburg Landau ◽  
Systematic Perturbation

The bifurcation from a normally conducting to a superconducting state as an external magnetic field is lowered is examined using the Ginzburg-Landau theory. The results for three specific examples are reviewed, extended and unified in the framework of a systematic perturbation theory introduced in [1].

Nucleation of superconductivity in decreasing fields. II

1994 ◽  
Vol 5 (4) ◽  
pp. 469-494 ◽  
Author(s):  
S. J. Chapman
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Nonlinear Stability ◽  
Bifurcation Point ◽  
Superconducting State ◽  
Landau Theory ◽  
Ginzburg Landau ◽  
Weakly Nonlinear ◽  
Stability Analyses

The bifurcation from a normally conducting to a superconducting state as an external magnetic field is lowered is examined using the Ginzburg–Landau theory. Linear and weakly nonlinear stability analyses are performed near the bifurcation point, and the implications of the results for each of three examples is considered.

Dynamics of vortex–antivortex creation and annihilation in current-driven mesoscopic superconducting squares

2015 ◽  
Vol 29 (35n36) ◽  
pp. 1550247
Author(s):  
Xiao-Meng Liang ◽  
Guo-Qiao Zha
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Landau Theory ◽  
Symmetric Case ◽  
Time Dependent ◽  
Dynamical Process ◽  
Applied Bias ◽  
Ginzburg Landau ◽  
Dc Drive ◽  
Vortex Velocity

In this paper, based on the time-dependent Ginzburg–Landau theory, we study the dynamics of vortex–antivortex (V–Av) pairs in a mesoscopic superconducting square with a small hole under applied bias currents. For the sample with a centered hole, a V–Av pair can nucleate at the hole edges and moves in opposite directions perpendicular to applied constant DC drive. The influence of the external magnetic field on the (anti)vortex velocity and the lifetime of V–Av pairs is mainly investigated. Different modes in the dynamical process of the V–Av collision and annihilation are identified. Moreover, in the case when the hole is displaced from the center of the square, the V–Av dynamics behaves quite differently from the symmetric case due to the shift of the V–Av creation point.

Vortices of mesoscopic rings in an external magnetic field: Phenomenological Ginzburg-Landau theory

2009 ◽  
Vol 79 (18) ◽  
Author(s):  
Liang-Ma Shi ◽  
Ling-Feng Zhang ◽  
Hao Meng ◽  
Hong-Wei Zhao ◽  
Guo-Qiao Zha ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Landau Theory ◽  
Ginzburg Landau

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.

scholarly journals Persistence of superconductivity in thin shells beyond Hc1

2016 ◽  
Vol 18 (04) ◽  
pp. 1550047 ◽  
Author(s):  
Andres Contreras ◽  
Xavier Lamy
Keyword(s):  
Magnetic Field ◽  
Model Problem ◽  
Landau Theory ◽  
Normal Component ◽  
Mean Field ◽  
Compact Surface ◽  
Thin Shells ◽  
Symmetric Model ◽  
Ginzburg Landau ◽  
Zero Locus

In Ginzburg–Landau theory, a strong magnetic field is responsible for the breakdown of superconductivity. This work is concerned with the identification of the region where superconductivity persists, in a thin shell superconductor modeled by a compact surface [Formula: see text], as the intensity [Formula: see text] of the external magnetic field is raised above [Formula: see text]. Using a mean field reduction approach devised by Sandier and Serfaty as the Ginzburg–Landau parameter [Formula: see text] goes to infinity, we are led to studying a two-sided obstacle problem. We show that superconductivity survives in a neighborhood of size [Formula: see text] of the zero locus of the normal component [Formula: see text] of the field. We also describe intermediate regimes, focusing first on a symmetric model problem. In the general case, we prove that a striking phenomenon we call freezing of the boundary takes place: one component of the superconductivity region is insensitive to small changes in the field.

scholarly journals Vortex guide under a Lorentz force

2020 ◽  
pp. 101-106
Author(s):  
C. A. Aguirre ◽  
Q. Martins ◽  
Jose Barba
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
External Magnetic Field ◽  
Lorentz Force ◽  
Vortex State ◽  
Cooper Pairs ◽  
Magnetic Response ◽  
External Current ◽  
Critical Temperatures ◽  
Ginzburg Landau

In the present work we studied the effect of the nature of the contacts, by which a weak external current is applied, in an anisotropic superconducting rectangle, on the magnetization, magnetic susceptibility, density of the Cooper pairs and  (magnetic field for which the first vortices entry on the sample). The contacts are simulates by the  parameter, and the anisotropy is present in sections with different critical temperatures modeling for  function, both in the Ginzburg-Landau formalis. Also, the sample is embebbed in an external magnetic field . We established how the nature of the contacts and the presence of a weak Lorentz Force, influence the magnetic response and the vortex state of the sample.

scholarly journals A perturbation theory approach to the ground state exciton energy in the limit of a weak magnetic field in anomalous exciton Hall effect

2021 ◽  
Vol 2015 (1) ◽  
pp. 012135
Author(s):  
V A Shabashov ◽  
V K Kozin ◽  
A V Kavokin ◽  
I A Shelykh
Keyword(s):  
Magnetic Field ◽  
Perturbation Theory ◽  
Dipole Moment ◽  
External Magnetic Field ◽  
Hall Effect ◽  
Ground State ◽  
Weak Magnetic Field ◽  
State Energy ◽  
Theory Approach ◽  
Exciton Energy

Abstract The anomalous exciton Hall effect is a phenomenon that occurs in a quantum well in the presence of an external magnetic field applied perpendicular to the surface due to the interaction of the exciton dipole moment with an electric field, formed by the charged impurities. The effect was fully described in [1] for different magnetic field regimes. In this paper, we focus on the way the perturbation method was used for finding the ground state energy of an exciton in the limit of a weak magnetic field.

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