Topological Defects in the Flux-Line Lattice and Their Relationship to the Critical Current of a Type-II Superconductor

F. Pardo; F. De La Cruz; P. L. Gammel; C. S. Oglesby; E. Bucher; B. Batlogg; D. J. Bishop

doi:10.1103/PhysRevLett.78.4633

Topological Defects in the Flux-Line Lattice and Their Relationship to the Critical Current of a Type-II Superconductor

F. Pardo, F. De La Cruz, P. L. Gammel, C. S. Oglesby, E. Bucher, B. Batlogg, and D. J. Bishop

Phys. Rev. Lett. 78, 4633 – Published 16 June 1997

Abstract

We report on a detailed magnetic decoration study of the real-space structure of the flux-line lattice (FLL) in NbS $e_{2}$ . We find two types of topological defects with different behaviors as a function of applied current and history. Isolated dislocations anneal with increasing current but peak at the critical current $J_{c}$ , being related to the microscopic disorder in the sample related to $J_{c}$ . The density of FLL grain boundaries is independent of current below $J_{c}$ but drops abruptly at $J_{c}$ , being the result of FLL nucleation effects and not affecting $J_{c}$ . We also report on current-induced hexatic order in the FLL.