Possible fluctuation origin of the anomalies in the c-axis magnetoresistance observed in Bi2Sr2CaCu2O8+x above the critical temperature
Balestrino G., Milani E., Varlamov A. A.
From the theory of fluctuation contribution to the о axis conductivity of layered •uperconductors under an external magnetic field recently developed by Dorm et al. an expression for the transverse magnetoresistance above Tc has been derived. The suppression of fluctuations due to the magnetic field leads to a decrease of the negative fluctuation contribution to conductance, and therefore to a negative transverse roagnetoresistance at temperatures not too close to Tc. The formula derived from the theory has been compared with the available experimental data of the magnetoresistance of BSCCO single crystals obtained by Ong et al. at temperatures 10-20 К above Tc. Both the quadratic increase of the relative magnetoresistance with field and its temperature dependence are well explained. A quantitative fit to the experimental data shows a remarkable agreement of the theory with experiment, and allows to extract the values of several physical parameters.