STUDY OF ANISOTROPIC MAGNETORESISTANCE IN THE THERMODYNAMIC FLUCTUATION REGIME OF SINGLE-CRYSTALS OF BI2SR2CACU2O8+X

Measurements of the in-plane and out-of-plane magnetoresistance in Bi2 Sr2CaCu2O8+x single crystals with a critical temperature T-c=93 K are reported for temperatures between T-c and 200 K and in magnetic fields up to 13 T. Both the transverse and the longitudinal in-plane magneto resistance are positive and originate entirely from the suppression of superconducting fluctuations by the magnetic field The longitudinal o ut-of-plane magnetoresistance is negative at all temperatures and magn etic fields. As possible origins two recent models are discussed, the reduction of the quasiparticle density of states due to condensation i nto superconducting fluctuations and thermally activated transport ove r an interplane pseudogap.