Spin dependence of pair tunneling properties of Bi2Sr2CaCu2O8+x intrinsic Josephson junctions

Abstract

Detailed tunneling characteristics of a stack of intrinsic Josephson junctions in a Bi2Sr2CaCu2O8+x single crystal were obtained both in spin-degenerate and spin-polarized bias configurations. Injection of the spin-polarized quasiparticles effectively weakened the in-plane superconducting strength and the interlayer Jospehson coupling. The superconducting gap and the Josephson critical current, of the stack were, in general, further suppressed by an external field applied in parallel with the c-axis direction. Study of the spin-dependent tunneling characteristics may provide valuable information on clarifying the mechanism of high-T-c superconductivity as well as the interlayer phase fluctuation induced by the "pancake vortices" on CuO2 layers.