High-field resistivity along the c-axis of single crystalline Bi2Sr2CaCu2O8+delta

The c-axis linear resistivity of Bi2Sr2CaCu2O8+delta has been measured in high fields up to 20.1 T applied to the c-axis, The strong field dependent up-turn behavior observed in high fields indicates that the normal state electronic state along the c-axis is not simple and conventional, but may be intrinsically insulating in this compound. This implies that the compound behaves essentially as a two-dimensional electronic system at low temperatures. This two-dimensional ground state behavior may give a strong limitation on the mechanism of high temperature superconductivity. Secondly, the c-axis linear resistivity tends to become zero at the irreversibility line, suggesting that a phase transition in the vortex state may exist at the irreversibility line even up to 20.1 T. Neither abrupt change at T-irr nor non-local effect of the resistivity above T-irr is found within our experimental accuracy.