ANISOTROPIC SUPERCONDUCTING PROPERTIES OF A TL-2223 SINGLE-CRYSTAL STUDIED BY TRANSPORT MEASUREMENTS

We reported a resistive study of a Tl2Ba2Ca2Cu3O10-delta (Tl-2223) sin gle crystal with magnetic fields up to 7 T applied in the two orientat ions H parallel-to c and H parallel-to ab. We obtained the anisotropic upper critical lines H(c2)(T) and the irreversibility lines H(irr)(T) . The derivation of the coherence lengths leads to a rather small anis otropic ratio and exhibits a correlation between the coherence length along the c-axis and the thickness of the Cu-O layers. Different model s of dissipation proposed in the literature have been unsuccessfully t ested and, in particular, the occurrence of a 2D fluctuation mechanism was not observed in the studied part of the phase diagram.