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

Abstract

In this paper we use London Langevin molecular dynamics simulations to investigate the vortex matter melting transition in the highly anisotropic high-temperature superconductor material Bi_2Sr_2CaCu_2O${}_{8+\delta }$ in the presence of low concentration of columnar defects (CDs). We reproduce with further details our previous results obtained by using Multilevel Monte Carlo simulations that showed that the melting of the nanocrystalline vortex matter occurs in two stages: a first stage melting into nanoliquid vortex matter and a second stage delocalization transition into a homogeneous liquid. Furthermore, we report on new dynamical measurements in the presence of a current that identifies clearly the irreversibility line and the second stage delocalization transition. In addition to CDs aligned along the c-axis we also simulate the case of tilted CDs which are aligned at an angle with respect to the applied magnetic field. Results for CDs tilted by $45^{\circ }$ with respect to c-axis show that the locations of the melting and delocalization transitions are not affected by the tilt when the ratio of flux lines to CDs remains constant. On the other hand we argue that some dynamical properties and in particular the position of the irreversibility line should be affected.

arXiv comment13 pages, 11 figures

References in corpus (20)

• The Flux-Line Lattice in Superconductors
• Crossing lattices, vortex chains, and angular dependence of melting line in layered superconductors
• Resurrection of the Melting Line in the Bose Glass Superconductor
• Melting of 'porous' vortex matter
• First order phase transition from the vortex liquid to an amorphous solid
• Evidence for vortex staircases in the whole angular range due to competing correlated pinning mechanisms
• Vortex nanoliquid in high-temperature superconductors
• Numerical study of vortex matter using the Bose model: First-order melting and entanglement
• Two-step melting of the vortex solid in layered superconductors with random columnar pins
• Pancake vortices
• Defect-unbinding and the Bose-glass transition in layered superconductors
• Delocalization in two dimensional disordered Bose systems and depinning transition in the vortex state in superconductors
• Interpolation of the Josephson interaction in highly anisotropic superconductors from a solution of the two dimensional sine-Gordon equation
• Effects of columnar disorder on flux-lattice melting in high-temperature superconductors
• 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
• Transverse Meissner Physics of Planar Superconductors with Columnar Pins
• On the melting of the nanocrystalline vortex matter in high-temperature superconductors
• Evidence for an angular dependent contribution from columnar defects to the equilibrium magnetization of YBa_2Cu_3O_{7-d}
• Molecular Dynamics of pancake vortices with realistic interactions: Observing the vortex lattice melting transition

Cited by in corpus (4)

• Multiple Changes of Order of the Vortex Melting Transition in BSCCO with Dilute Columnar Defects
• Non-classical Rotational Inertia in a Two-dimensional Bosonic Solid Containing Grain Boundaries
• 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