scholarly journals Ultra-fast kinematic vortices in mesoscopic superconductors: the effect of the self-field

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Leonardo Rodrigues Cadorim ◽  
Alexssandre de Oliveira Junior ◽  
Edson Sardella
Keyword(s):  
Characteristic Curve ◽  
Vortex Street ◽  
Resistive State ◽  
Ginzburg Landau ◽  
Normal Contact ◽  
Material Inhomogeneity ◽  
Mesoscopic Superconductors ◽  
Ginzburg Landau Equations ◽  
Superconducting Sample ◽  
Sample Width

Abstract Within the framework of the generalized time-dependent Ginzburg–Landau equations, we studied the influence of the magnetic self-field induced by the currents inside a superconducting sample driven by an applied transport current. The numerical simulations of the resistive state of the system show that neither material inhomogeneity nor a normal contact smaller than the sample width are required to produce an inhomogeneous current distribution inside the sample, which leads to the emergence of a kinematic vortex–antivortex pair (vortex street) solution. Further, we discuss the behaviors of the kinematic vortex velocity, the annihilation rates of the supercurrent, and the superconducting order parameters alongside the vortex street solution. We prove that these two latter points explain the characteristics of the resistive state of the system. They are the fundamental basis to describe the peak of the current–resistance characteristic curve and the location where the vortex–antivortex pair is formed.

HALF-CIRCULAR PILLAR IN A SUPERCONDUCTING SAMPLE

2013 ◽  
Vol 27 (12) ◽  
pp. 1350087 ◽  
Author(s):  
J. BARBA-ORTEGA ◽  
SINDY J. HIGUERA ◽  
J. ALBINO AGUIAR
Keyword(s):  
Boundary Condition ◽  
Normal State ◽  
Critical Fields ◽  
Ginzburg Landau ◽  
Ginzburg Landau Equations ◽  
Superconducting Sample

In this paper, we solve the Ginzburg–Landau equations for a circular geometry containing a half-circular pillar. We consider the surface of the sample in a complete normal state (|ψ| surface = 0), this choice, leading to take the extrapolation de Gennes length equal to zero (b = 0). Our results point out that the critical fields, magnetization and vorticity, depend on the chosen boundary condition.

scholarly journals Dimer structure as topological pinning center in a superconducting sample

2020 ◽  
Vol 19 (1) ◽  
pp. 109-115 ◽  
Author(s):  
Cristian A Aguirre ◽  
MiryamR. Joya ◽  
J. Barba-Ortega
Keyword(s):  
Magnetic Field ◽  
Pulsed Laser ◽  
Vortex State ◽  
Vortex Matter ◽  
Ginzburg Landau ◽  
Pinning Centers ◽  
Dimer Structure ◽  
Ginzburg Landau Equations ◽  
Superconducting Sample ◽  
Pinning Center

Solving the Ginzburg-Landau equations, we analyzed the vortex matter in a superconducting square with a Dimer structure of circular pinning centers generated by a pulsed heat source in presence of an applied magnetic field. We numerically solved the Ginzburg-Landau equations in order to describe the effect of the temperature of the circular defects on the Abrikosov state of the sample. The pulsed laser produced a variation of the temperature in each defect. It is shown that an anomalous vortex-anti-vortex state (A-aV) appears spontaneously at higher magnetic fields. This could be due to the breaking of the symmetry of the sample by the inclusion of the thermal defects

scholarly journals Random distribution of topological defects in mesoscopic superconducting samples

Respuestas ◽  
2020 ◽  
Vol 25 (1) ◽  
pp. 178-183
Author(s):  
Oscar Silva-Mosquera ◽  
Omar Yamid Vargas-Ramirez ◽  
José José Barba-Ortega
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Random Distribution ◽  
Topological Defects ◽  
Ginzburg Landau ◽  
Field Function ◽  
Strong Anchor ◽  
Different Temperatures ◽  
Ginzburg Landau Equations ◽  
Superconducting Sample

In the present work we analyze the effect of topological defects at different temperatures in a mesoscopic superconducting sample in the presence of an applied magnetic field H. The time-dependent Ginzburg-Landau equations are solved with the method of link variables. We study the magnetization curves M(H), number of vortices N(H) and Gibbs G(H) free energy of the sample as a applied magnetic field function. We found that the random distribution of the anchor centers for the temperatures used does not cause strong anchor centers for the vortices, so the configuration of fluxoids in the material is symmetrical due to the well-known Beam-Livingston energy barrier.

Vortex states in mesoscopic superconductors with a complex geometry: A finite element analysis

2014 ◽  
Vol 28 (20) ◽  
pp. 1450127 ◽  
Author(s):  
Lin Peng ◽  
Zejiang Wei ◽  
Danhua Xu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Complex Geometry ◽  
Dimensional Space ◽  
Dynamical Behavior ◽  
Element Analysis ◽  
Ginzburg Landau ◽  
Mesoscopic Superconductor ◽  
Mesoscopic Superconductors ◽  
Ginzburg Landau Equations

The time-dependent Ginzburg–Landau equations have been solved numerically by a finite-element analysis for a mesoscopic superconducting square structure with four nanoscale holes in two-dimensional space. For given applied magnetic fields we have simulated the dynamical behavior of the penetrating magnetic vortices into the superconductor. Our results show that the mesoscopic superconductor can be tuned to exhibit the clear separation of the multivortex by properly introducing the nanoscale holes in a mesoscopic superconductor.

PATTERNS, DEFECTS, AND EVOLUTION OF BÉNARD–MARANGONI CELLS

1996 ◽  
Vol 06 (09) ◽  
pp. 1665-1671 ◽  
Author(s):  
J. BRAGARD ◽  
J. PONTES ◽  
M.G. VELARDE
Keyword(s):  
Fluid Layer ◽  
Ambient Air ◽  
Finite Geometry ◽  
Amplitude Equations ◽  
Ginzburg Landau ◽  
Weakly Nonlinear ◽  
Numerical Exploration ◽  
Ginzburg Landau Equations ◽  
Rigid Plane ◽  
Selection Of

We consider a thin fluid layer of infinite horizontal extent, confined below by a rigid plane and open above to the ambient air, with surface tension linearly depending on the temperature. The fluid is heated from below. First we obtain the weakly nonlinear amplitude equations in specific spatial directions. The procedure yields a set of generalized Ginzburg–Landau equations. Then we proceed to the numerical exploration of the solutions of these equations in finite geometry, hence to the selection of cells as a result of competition between the possible different modes of convection.

Geometric effect on the vortex configuration and motion in mesoscopic superconducting cylinders

2015 ◽  
Vol 29 (03) ◽  
pp. 1550009 ◽  
Author(s):  
Shan-Shan Wang ◽  
Guo-Qiao Zha
Keyword(s):  
Phase Transitions ◽  
Vortex Dynamics ◽  
Axial Symmetry ◽  
Time Dependent ◽  
Vortex Matter ◽  
Ginzburg Landau ◽  
Geometric Effect ◽  
Multiply Connected ◽  
Vortex States ◽  
Ginzburg Landau Equations

Based on the time-dependent Ginzburg–Landau equations, we study numerically the vortex configuration and motion in mesoscopic superconducting cylinders. We find that the effects of the geometric symmetry of the system and the noncircular multiply-connected boundaries can significantly influence the steady vortex states and the vortex matter moving. For the square cylindrical loops, the vortices can enter the superconducting region in multiples of 2 and the vortex configuration exhibits the axial symmetry along the square diagonal. Moreover, the vortex dynamics behavior exhibits more complications due to the existed centered hole, which can lead to the vortex entering from different edges and exiting into the hole at the phase transitions.

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