Vortex dynamics and critical current in superconductors with unidirectional twin boundaries

Asai, Hidehiro; Watanabe, Satoshi

doi:10.1103/physrevb.77.224514

Cited by 8 publications

(10 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…10 The onset of different dynamical phases as a function of external driving has been observed in various overdamped systems, including colloids and vortices moving over q1D periodic substrates, but only for a driving force applied parallel to the substrate periodicity direction. In those systems there is generally a disordered flow phase above depinning 7,14,47,48 with a transition to a moving ordered phase at higher drives 14,47,48 ; however, negative differential conductivity does not occur. For systems of particles moving over 2D periodic substrates, such as egg carton or muffin tin potentials, negative differential conductivity can arise 18,20,[49][50][51] .…”

Section: Collective Effectsmentioning

confidence: 99%

Magnus-induced dynamics of driven skyrmions on a quasi-one-dimensional periodic substrate

Reichhardt

2016

Phys. Rev. B

View full text Add to dashboard Cite

We numerically examine driven skyrmions interacting with a periodic quasi-one dimensional substrate where the driving force is applied either parallel or perpendicular to the substrate periodicity direction. For perpendicular driving, the particles in a purely overdamped system simply slide along the substrate minima; however, for skyrmions where the Magnus force is relevant, we find that a rich variety of dynamics can arise. In the single skyrmion limit, the skyrmion motion is locked along the driving or longitudinal direction for low drives, while at higher drives a transition occurs to a state in which the skyrmion moves both transverse and longitudinal to the driving direction. Within the longitudinally locked phase we find a pronounced speed up effect that occurs when the Magnus force aligns with the external driving force, while at the transition to transverse and longitudinal motion, the skyrmion velocity drops, producing negative differential conductivity. For collectively interacting skyrmion assemblies, the speed up effect is still present and we observe a number of distinct dynamical phases, including a sliding smectic phase, a disordered or moving liquid phase, a moving hexatic phase, and a moving crystal phase. The transitions between the dynamic phases produce distinct features in the structure of the skyrmion lattice and in the velocity-force curves. We map these different phases as a function of the ratio of the Magnus term to the dissipative term, the substrate strength, the commensurability ratio, and the magnitude of the driving force.

show abstract

Section: Collective Effectsmentioning

confidence: 99%

Magnus-induced dynamics of driven skyrmions on a quasi-one-dimensional periodic substrate

Reichhardt

2016

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…Numerical studies of vortex behavior in the presence of planar defects range from solving the full time-dependent Ginzburg-Landau equations [29][30][31][32] to more approximate descriptions [33][34][35][36][37] of vortices in two-dimensional thinfilm and three-dimensional bulk samples as structureless pointor string-like objects that are studied with either Monte Carlo simulations or Langevin dynamics methods. The experimentally detected anisotropy of pinning and transport has been observed in numerical simulations of twinned superconductors [38,39] with thermal fluctuations being enhanced and vortex motion facilitated within defect planes. Reichhardt et al identified three phases of flux flow in London-Langevin studies of driven vortices subject to planar pinning, viz.…”

Section: Introductionmentioning

confidence: 83%

Dynamical regimes of vortex flow in type-II superconductors with parallel twin boundaries

et al. 2018

View full text Add to dashboard Cite

We explore the dynamics of driven magnetic flux lines in disordered type-II superconductors in the presence of twin boundaries oriented parallel to the direction of the applied magnetic field, using a three-dimensional elastic line model simulated with Langevin molecular dynamics. The lines are driven perpendicular to the planes to model the effect of an electric current applied parallel to the planes and perpendicular to the magnetic field. A study of the long-time non-equilibrium steady states for varying sample orientation and thickness reveals a rich collection of dynamical regimes spanning the depinning crossover region that separates the pinned and moving-lattice states of vortex matter. We observe the emergence of a preferred direction for the ordering of the Abrikosov lattice in the free-flowing vortex regime due to asymmetric pinning by the planar defects. We have performed novel direct measurements of flux line excitations such as half-loops and double kinks to aid the characterization of the topologically rich flux flow profile.

show abstract

“…The red magnified area represents the GB model and the GB is modeled as an attractive well, 2d is the effective width of the GB and d is taken as 0.15λ . [22,24,28] In the GB region, a series of red dots indicates dislocations, and the red arrows acting on vortices denote the directions of electric forces. H and I refer to the applied magnetic field and transport current, respectively.…”

Section: Model For Vortex Dynamicsmentioning

confidence: 99%

“…[21][22][23] Although numerous studies of thin films and bulk samples have evaluated the influence of grain boundaries (GBs) on vor-tex motion, they mainly focused on the circumstances of parallel GBs or a single GB. [22][23][24][25] As is well known, the role of the GB which can be changed from a barrier to an easy-flow channel is intrinsically determined by the competitive effect associated with the action on vortex between in the GB and intragranular region, and also affected by the angle between the grain boundary and the applied current based on previous work. [26] The investigations on random GB networks with complex orientations which can model polycrystalline materials also play a crucial role in gaining a deeper knowledge about grain boundary mechanism on vortex motion.…”

Section: Introductionmentioning

confidence: 99%

Role of grain boundary networks in vortex motion in superconducting films

2023

View full text Add to dashboard Cite

We studied the vortex dynamics of the polycrystalline superconductors in the presence of both random point defects and the generated grain boundary (GB) networks with voronoi diagram. The synergistic effect of adjacent GBs on restricting the vortex motion in intragranular region is proposed and the corresponding intensity factor of the synergistic effect which characterizes the strength of the synergistic restriction of adjacent grain boundaries is also defined in the present paper. The interconnected GBs offer easy-flow channels for vortices in addition to pinning effects on the vortices. The combined channels and the vortex flow patterns in the superconducting film are analyzed in detail from molecular dynamics simulations. Furthermore, it is discovered that the critical current increases with decreasing magnetic field intensity, temperature, and the average grain size. The large number of vortices results in the enhanced repulsive interaction forcing the vortices moving out from the GBs. The thermal depinning from GBs leads to the lower Lorentz force range. The increase of the grain size causes the number of GBs decreasing. In summary, these effects result in the critical current being a decreasing function of magnetic field, temperature, and grain size.

show abstract

Vortex dynamics and critical current in superconductors with unidirectional twin boundaries

Cited by 8 publications

References 40 publications

Magnus-induced dynamics of driven skyrmions on a quasi-one-dimensional periodic substrate

Magnus-induced dynamics of driven skyrmions on a quasi-one-dimensional periodic substrate

Dynamical regimes of vortex flow in type-II superconductors with parallel twin boundaries

Role of grain boundary networks in vortex motion in superconducting films

Contact Info

Product

Resources

About