Effect of spin-polarized current injection on pair tunneling properties of <TEX>$Bi_2$</TEX><TEX>$Sr_2$</TEX>Ca<TEX>$Cu_2$</TEX><TEX>$O_{8+x}$</TEX> intrinsic Josephson junctions

We studied the effect of spin injection on tunneling conduction properties of intrinsic Josephson junctions formed in <TEX>$Bi_2$</TEX><TEX>$Sr_2$</TEX><TEX>$CaCu_2$</TEX><TEX>$O_{ 8＋x}$</TEX> single crystals. properties of an identical stack (10<TEX>${ imes}$</TEX>5.0<TEX>${ imes}$</TEX>0.030 <TEX>$mu extrm{m}^3$</TEX>) of intrinsic Josephson junctions were compared for the bias current injected through Au and Co electrodes. The suppression of the superconducting gap in the <TEX>$_2$</TEX> double layers and the interlayer Josephson critical current was manifested in the tunneling current-voltage characteristics of the stacks. This effect appears to be caused by the pair breaking associated with spin-polarized carriers injected from the Co electrode into the <TEX>$Bi_2$</TEX><TEX>$Sr_2$</TEX><TEX>$_2$</TEX>O<TEX>$CaCu_{ 8＋x}$</TEX> single crystal. This study may provide valuable information on clarifying the mechanism of high- <TEX>$T_{c}$</TEX> superconductivity.y.y.