C-axis negative magnetoresistance and upper critical field of Bi2Sr2CaCu2O8

The out-of-plane resistance and the resistive upper critical field of BSCCO-2212 single crystals with T-c0 similar or equal to 91-93 K have been measured in magnetic fields up to 50 T over a wide temperature range. The results are characterised by a positive linear magnetoresistance in the superconducting state and negative linear magnetoresistance in the normal state. The zero-field normal-state c-axis resistance, the negative linear normal-state magnetoresistance, and the divergent upper critical field H-c2(T) are explained in the framework of the bipolaron theory of superconductivity.