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Time dependent Ginzburg-Landau equation is solved for type II superconductors numerically, and the dynamics of entering vortices, geometric defects and pinning effects have been investigated. A superconducting wire with ratchet defects is…

Superconductivity · Physics 2017-04-06 Dachuan Lu

Vortices in a narrow superconducting strip with a square array of pinning sites are studied. The interactions of vortices with other vortices and with external sources (applied magnetic field and transport current) are calculated via a…

Superconductivity · Physics 2009-11-07 Clécio C. de Souza Silva , Leonardo R. E. Cabral , J. Albino Aguiar

We use numerical minimization of a model free energy functional to study the effects of columnar pinning centers on the structure and thermodynamics of a system of pancake vortices in the mixed phase of highly anisotropic layered…

Superconductivity · Physics 2009-11-07 Chandan Dasgupta , Oriol T. Valls

Superconducting critical currents $j_{c} > 10^{5}$ A/cm$^{2}$ at temperatures $T \sim 50$ K and magnetic fields $B \sim 6$ T are reported for the YBa$_{2}$Cu$_{3-x}$Mo$_{x}$O$_{7+d}$ compound with $x = 0.02$. Clear evidence for the…

Superconductivity · Physics 2009-11-11 K. Rogacki , B. Dabrowski , O. Chmaissem

Vortex motion plays a central role in determining the resistance of two-dimensional superconductors, both in the context of the Berezinskii-Kosterlitz-Thouless (BKT) transition and in the mixed state of type-II superconductors under…

Superconductivity · Physics 2025-06-09 Zhipeng Xu , Kun Jiang , Jiangping Hu

We study the 2D full Ginzburg-Landau energy with a periodic rapidly oscillating, discontinuous and [strongly] diluted pinning term using a perturbative argument. This energy models the state of an heterogeneous type II supercon-ductor…

Analysis of PDEs · Mathematics 2019-04-05 Mickaël Dos Santos

A theoretical framework is presented, which allows to explain many experimental facts related to pinning and cross-flow effects between flux tubes in type-II superconductors. It is shown that critical state principles, in the manner…

Superconductivity · Physics 2007-05-23 A. Badia , C. Lopez

We study the critical depinning current Jc versus the applied magnetic flux Phi, for quasiperiodic (QP) chains and 2D arrays of pinning centers placed on the nodes of a five-fold Penrose lattice. In QP chains, the peaks in Jc(Phi) are…

Superconductivity · Physics 2021-03-16 V. R. Misko , Sergey Savel'ev , Franco Nori

In magnetic superconductors vortices polarize spins nonuniformly and repolarize them when moving. At a low spin relaxation rate and at low bias currents vortices carrying magnetic polarization clouds become polaron-like and their velocities…

Superconductivity · Physics 2013-10-16 Lev N. Bulaevskii , Shi-Zeng Lin

Disorder induced melting, where the increase in positional entropy created by random pinning sites drives the order-disorder transition in a periodic solid, provides an alternate route to the more conventional thermal melting. Here, using…

Strong pinning of superconducting flux quanta by a square array of 1 $\mu$m-sized ferromagnetic dots in a magnetic-vortex state was visualized by low-temperature magnetic force microscopy (LT-MFM). A direct correlation of the…

Superconductivity · Physics 2010-03-18 T. Shapoval , V. Metlushko , M. Wolf , B. Holzapfel , V. Neu , L. Schultz

We show using simulations that when interstitial vortices are present in superconductors with periodic pinning arrays, the transport in two perpendicular directions can be anisotropic. The degree of the anisotropy varies as a function of…

Superconductivity · Physics 2009-11-13 C. Reichhardt , C. J. Olson Reichhardt

Using computer simulations, we demonstrate a new type of commensurability that occurs for vortices moving longitudinally through periodic pinning arrays in the presence of an additional transverse driving force. As a function of vortex…

Superconductivity · Physics 2009-11-13 C. Reichhardt , C. J. Olson Reichhardt

We examine vortex dynamics and pinning in layered superconductors using three-dimensional molecular dyanmics simulations of magnetically interacting pancake vortices. Our model treats the magnetic interactions of the pancakes exactly, with…

Superconductivity · Physics 2015-06-24 Charles Reichhardt , Cynthia J. Olson , Niels Gronbech-Jensen

We study experimentally the critical depinning current Ic versus applied magnetic field B in Nb thin films which contain 2D arrays of circular antidots placed on the nodes of quasiperiodic (QP) fivefold Penrose lattices. Close to the…

Superconductivity · Physics 2007-05-23 M. Kemmler , C. Guerlich , A. Sterck , H. Poehler , M. Neuhaus , M. Siegel , R. Kleiner , D. Koelle

A true critical current density, $j_{c}$, as opposite to commonly measured relaxed persistent (Bean) current, $j_{B}$, was extracted from the Campbell penetration depth, $\lambda_{C}(T,H)$ measured in single crystals of LiFeAs. The…

Vortices in type-II superconductors driven over random disorder are known to exhibit a remarkable variety of distinct nonequilibrium dynamical phases that arise due to the competition between vortex-vortex interactions, the quenched…

Superconductivity · Physics 2025-01-24 C. J. O. Reichhardt , D. McDermott , C. Reichhardt

Nonreciprocal supercurrent refers to the phenomenon where the maximum dissipationless current in a superconductor depends on its direction of flow. This asymmetry underlies the operation of superconducting diodes and is often associated…

We identify a phase transition in the vortex system of a high-temperature superconductor with nano-columnar stacks of precipitates as strong vortex pinning centers. Above a particular, temperature-dependent field $B_X(T)$ the vortex…

Superconductivity · Physics 2015-05-30 Yuri L. Zuev , Sung Hun Wee , David K. Christen

We show that a magnetic strip on top of a superconducting strip magnetized in a specified direction may considerably enhance the critical current in the sample. At fixed magnetization of the magnet we observed diode effect - the value of…

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