The critical fluctuations and pinning effects in the vortex state of twinned superconducting Y-Ba-Cu-O single crystals are investigated. A second-order vortex-solid melting transition is manifested by the universal static and dynamic exponents ν≊2/3 and z≊3 and the universal vortex-transport functions, independent of the experimental techniques and the magnitude and orientation of the applied magnetic fields. The vortex-correlation length and the critical-relaxation rate are also determined.

• Received 2 October 1992

DOI:https://doi.org/10.1103/PhysRevB.47.6146