Muon-spin-relaxation study on the Cu-spin state of Bi2Sr2Ca1-xYx(Cu1-yZny)2O8+δ around the hole concentration of 1/8 per Cu

Muon-spin-relaxation (mu SR) measurements were applied to the partially Zn-substituted Bi-2212 system, Bi2Sr2Ca1-xYx(Cu1-yZny)(2)O8+delta, to study the Cu-spin state in a wide range of the hole concentration, p. Singularity of the magnetic correlation between Cu spins at p similar to1/8 per Cu has been confirmed clearly, proving the existence of the so-called 1/8 effect in the Bi-2212 system. The muon-spin depolarization rate of the Zn-substituted sample with p similar to 1/8 per Cu (x = 0.3125 and y = 0.025) at 0.30 K has been found to exhibit nearly a root-square dependence on the magnetic field;applied along the initial muon-spin direction. This field dependence can be explained by assuming that a magnetically excited state of Cu spins moves in a one-dimensional direction producing fluctuating internal fields at the muon sites. The present mu SR measurements may support the existence of the stripe correlations of spins and holes in the Bi-2212 system also.