Plastic deformation and vortex dynamics instability of the flux-line lattice in high-temperature superconductors

Abstract

Abstract The role of plastic deformations on the vortex dynamics instability of the fluxline lattice (FLL) in high-temperature superconductors is investigated. A model is proposed where elastic instability characterizes the FLL dynamics in a certain domain when the plastic energy of dislocation exceeds the pinning energy in that domain. Under these conditions, the velocity of the flux lines moving in this domain will change. Accordingly, the force—velocity relationship of the vortex lines or, equivalently, the I—V characteristics of the superconductor will experience the same change. A criterion for the appearance of the instability in the FLL is proposed by ΔE D/E pin ≥ 1, where ΔE D is the plastic energy of dislocation and E pin is the pinning energy of a rigid flux line. When this criterion is applied, the experimental measurements on superconducting YBa2Cu3O7-x thin films were reproduced. These results confirm the importance of plastic deformations in the behaviour of the FLL in superconductors.