Browsing by Author "Hung, R. F."

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Electrodynamics of type-II superconductor with periodic pinning array
(2011-01-01)
Hung, R. F.
;
Berco, D.
;
Shapiro, I. Ya
;
Shapiro, B.
;
Rosenstein, B.
Static and dynamic distribution of the superconducting condensate order parameters and current density is studied by numerical simulation of the 2D time-dependent Ginzburg-Landau equations The vortex flux lattice in layered type-II superconductors under magnetic field above the lower critical field is described by the order parameters Moreover the pinning effect has been considered in this work The Abrikosov lattice which is hexagonal in the static case is deformed due to the size of pinning centers The dynamical order parameters distribution shows that the vortex transport (flux flow) is conducted via diffusive motion of the so-called interstitial vortices The trajectories for interstitial vortices with different sizes of pinning centers are shown (C) 2010 Elsevier BV All rights reserved
Sliding Abrikosov lattice in a superconductor with a regular array of artificial pinning centers: AC conductivity and criticality at small frequencies
(2010-10-01)
Maniv, T.
;
Rosenstein, B.
;
Shapiro, I.
;
Shapiro, B. Ya.
;
Hung, R. F.
Dynamics of the flux lattice in the mixed state of strongly type-II superconductor near the upper critical field subjected to AC field and interacting with a periodic array of short range pinning centers is considered. The superconductor in a magnetic field in the absence of thermal fluctuations on is described by the time-dependent Ginzburg-Landau equations. For a special case of the delta-function shaped pinning centers and for pinning array commensurate with the Abrikosov lattice (so that vortices outnumber pinning centers) an analytic expression or the AC conductivity is obtained. It is found that below a certain critical pinning strength and for sufficiently low frequencies there exists a sliding Abrikosov lattice, which vibrates nearly uniformly despite interactions with the pinning centers. At very small frequencies the conductivity diverges at the critical pinning strength. (C) 2010 Elsevier B.V. All rights reserved.