Screw-dislocation-induced plasticization of a pinned vortex lattice

Abstract

The energy of vortex-lattice screw dislocations is computed numerically on the basis of the isotropic London approximation. The results of computation are applied to the collective-pinning theory proposed by Larkin and Ovchinnikov. The present modified pinning model predicts that a vortex lattice is stabilized by possessing many screw dislocations for sufficiently strong pinning. Then the spacing between slip planes nearly equals the vortex-lattice constant, where the Burgers vectors of two adjacent slip planes are in the opposite direction. Penetration of the screw dislocations induces sudden vortex-lattice plasticization, which can be observed as a discontinuous jump of the critical current. This prediction is compared with the critical-current abrupt rises observed in amorphous ${\mathrm{Nb}}_{x}\mathrm{Ge}$ films and in neutron-irradiated ${\mathrm{V}}_{3}\mathrm{Si}$ bulks.