LINDEMANN CRITERION AND VORTEX-MATTER PHASE-TRANSITIONS IN HIGH-TEMPERATURE SUPERCONDUCTORS

The vortex-matter in superconductors is generally believed to exist in two main phases, vortex-solid and vortex-liquid. Recent investigation s of the phase diagram of anisotropic high-temperature superconductors indicate, however, the existence of at least three distinct phases: r elatively ordered quasi-lattice, highly-disordered entangled vortex-so lid, and a liquid phase. A theoretical analysis in terms of an extende d Lindemann criterion provides a quantitative description of the resul ting vortex-matter phase boundaries and the behavior of the transition lines with varying anisotropy and disorder. (C) 1998 Elsevier Science B.V.