Point-defects-induced vortex phase diagram in high-Tc superconductors: Monte Carlo simulation study

Abstract

We investigated the vortex phase diagram of high-Tc copper-oxide superconductors in the presence of dense point defects (PDs), by using a Monte Carlo simulation based on the Lawrence–Doniach model. We found a temperature-driven depinning line within the Bragg and vortex glass phases, well below the melting line in the case of high anisotropy. We also found a field-driven transition line from the Bragg-to-vortex glass at low temperatures, accompanied by an abrupt reduction in the interlayer vortex correlation. The complex phase boundaries are drastically controlled by the pinning force of PDs, defect density, and anisotropy.