Effects of columnar disorder on flux-lattice melting in high-temperature superconductors

Abstract

The effect of columnar pins on the flux-lines melting transition in high-temperature superconductors is studied using Path Integral Monte Carlo simulations. We highlight the similarities and differences in the effects of columnar disorder on the melting transition in YBa${}_2$Cu${}_3$O${}_{7-\delta }$ (YBCO) and the highly anisotropic Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$ (BSCCO) at magnetic fields such that the mean separation between flux-lines is smaller than the penetration length. For pure systems, a first order transition from a flux-line solid to a liquid phase is seen as the temperature is increased. When adding columnar defects to the system, the transition temperature is not affected in both materials as long as the strength of an individual columnar defect (expressed as a flux-line defect interaction) is less than a certain threshold for a given density of randomly distributed columnar pins. This threshold strength is lower for YBCO than for BSCCO. For higher strengths the transition line is shifted for both materials towards higher temperatures, and the sharp jump in energy, characteristic of a first order transition, gives way to a smoother and gradual rise of the energy, characteristic of a second order transition. Also, when columnar defects are present, the vortex solid phase is replaced by a pinned Bose glass phase and this is manifested by a marked decrease in translational order and orientational order as measured by the appropriate structure factors. For BSCCO, we report an unusual rise of the translational order and the hexatic order just before the melting transition. No such rise is observed in YBCO.

arXiv comment32 pages, 13 figures, revtex

References in corpus (15)

• The Flux-Line Lattice in Superconductors
• Elastic theory of flux lattices in presence of weak disorder
• Vortex-glass phases in type-II superconductors
• Irreversibility, Mechanical Entanglement and Thermal Melting in Superconducting Vortex Crystals with Point Impurities
• Low-Field Phase Diagram of Layered Superconductors: The Role of Electromagnetic Coupling
• Resurrection of the Melting Line in the Bose Glass Superconductor
• Melting of 'porous' vortex matter
• Static and dynamic coupling transitions of vortex lattices in disordered anisotropic superconductors
• Entropy, vortex interactions, and the phase diagram of heavy-ion irradiated Bi_2Sr_2CaCu_2O_8
• Numerical study of vortex matter using the Bose model: First-order melting and entanglement
• Simulation of Flux Lines with Columnar Pins: Bose Glass and Entangled Liquids
• Defect-unbinding and the Bose-glass transition in layered superconductors
• Properties of the Bose glass phase in irradiated superconductors near the matching field
• Phase Transitions of the Flux Line Lattice in High-Temperature Superconductors with Weak Columnar and Point Disorder
• Effect of Vortex Screening on the Bose Glass to Entangled Liquid Transition of Flux Lines in Superconductors

Cited by in corpus (16)

• Mott insulator phases and first-order melting in BSCCO crystals with periodic surface holes
• Vortex nanoliquid in high-temperature superconductors
• Relaxation and Glassy Dynamics in Disordered Type-II Superconductors
• Interpolation of the Josephson interaction in highly anisotropic superconductors from a solution of the two dimensional sine-Gordon equation
• Flux melting in BSCCO: Incorporating both electromagnetic and Josephson couplings
• Bragg-Bose glass phase in vortex states of high-$T_{\mathrm{c}}$ superconductors with sparse and weak columnar defects
• Effective way to sum over long range Coulomb potentials in two and three dimensions
• Melting and structure of the vortex solid in strongly anisotropic layered superconductors with random columnar pins
• Phase diagram of the vortex system in layered superconductors with strong columnar pinning
• On the melting of the nanocrystalline vortex matter in high-temperature superconductors
• Langevin Dynamics of the vortex matter two-stage melting transition in Bi_2Sr_2CaCu_2O${}_{8+\delta }$ in the presence of straight and of tilted columnar defects
• Multiple Changes of Order of the Vortex Melting Transition in BSCCO with Dilute Columnar Defects
• Nonequilibrium steady states of driven magnetic flux lines in disordered type-II superconductors
• Molecular Dynamics of pancake vortices with realistic interactions: Observing the vortex lattice melting transition
• The phase diagram of vortex matter in layered superconductors with tilted columnar pinning centers
• Monte Carlo Simulation of the Crossover from Bose Glass to Bragg Glass Phase in Layered BSCCO with Columnar Defects