Phase-coherence transition in granular superconductors with π junctions

[摘要] We study the three-dimensional XY-spin glass as a model for the resistive behavior of granular superconductors containing a random distribution of pi junctions, as in high-T-c superconducting materials with d-wave symmetry. The pi junctions leads to quenched in circulating currents (chiralities) and to a chiral-glass state at low temperatures, even in the absence of an external magnetic field. Dynamical simulations in the phase representation are used to determine the nonlinear current-voltage characteristics as a function of temperature. Based on dynamic scaling analysis, we find a phase-coherence transition at finite temperature below which the linear resistivity should vanish and determine the corresponding critical exponents. The results suggest that the phase and chiralities may order simultaneously for decreasing temperatures into a superconducting chiral-glass state. (C) 2001 Elsevier Science B.V. All rights reserved.

[发布日期] 2001-05-01

[效力级别]  Proceedings Paper

[关键词] superconductors - high-T-c;granular systems;resistivity scaling;spin glass