Effect of small oxygen deficiency on the para-coherent transition and 2D-3D crossover in untwinned YBa2СuзО7−δ single crystals

▶ The application of a constant magnetic field to YBa2Cu3O7−δ single crystals leads to an additional para-coherent transition in the excess conductivity temperature dependences ▶ Increasing the angle α ≡ ∠(H,ab) leads to an increase of the amplitude and the width of the ▶ At T < Tc there is a suppression of the dynamic phase transition type liquid vortex-vortex lattice and the formation of transition in the system type liquid vortex-vortex “Bragg” glass. ▶ The FC near Tc is described by the 3D Aslamazov-Larkin model for layered superconducting systems. ▶ The increase in disorientation angle α ≡ ∠(H,ab) results to an increase of the temperature interval that the fluctuation para-conductivity regime is realized.