Strong three-dimensional correlations in the vortex system for (Bi0.7Pb0.3)(2.2)Sr2CaCu2O8

[摘要] An experimental study of magnetic flux penetration under crossed magnetic fields in Bi2212:Pb single crystals is performed by the magneto-optic technique. A remarkable field penetration pattern alteration and superconducting current anisotropy enhancement by the in-plane field is revealed. The anisotropy increases with the temperature rise up to T-m=54+/-2 K. At T=T-m an abrupt change in the flux penetration behavior is found. The correlation between the in-plane magnetic field and the out-of-plane magnetic flux penetration disappears and no correlation is observed at T>T-m. The transition temperature T-m does not depend on the magnetic field strength. The observed flux penetration anisotropy is considered as a evidence for a strong three-dimensional correlation between pancake vortices in different CuO planes at T

[关键词] LAYERED SUPERCONDUCTORS;HIGH-T(C) SUPERCONDUCTORS;DIMENSIONAL CROSSOVER;II SUPERCONDUCTORS;ANGULAR-DEPENDENCE;PHASE-TRANSITION;SINGLE-CRYSTALS;LATTICE;LINE;MAGNETIZATION