EFFECT OF THE MAGNETIC-FIELD ON THE C-AXIS RESISTANCE PEAK IN BI2SR2CACU2O8+X

The measurements of the our-of-plane component of resistivity rho(c)(T ,B) in magnetic field in high-quality epitaxial Bi2Sr2CaCu2O8+x films are presented. We found that rho(c)(T,B) exhibits a well-pronounced pe ak at the edge of the superconducting transition. Magnetic field cause s both a sizeable increase of the relative magnitude of the peak and a strong shift of its position to lower temperatures. We demonstrate th at zero-field data and data for weak magnetic fields B less than or eq ual to 1 T are well described within the fluctuation theory taking int o account Gaussian approximation in fluctuation behavior. Quantitative fit of the data in the framework of this theory allowed us to extract the effective anisotropy parameter, the quasiparticle relaxation time and the phase pair-breaking relaxation time. We discuss the reasons o f the discrepancy between theory and experiment for stronger magnetic fields.