Muon-spin-relaxation study of the effect of nonmagnetic impurities on the Cu-spin fluctuations in La_2-xSr_xCu_1-yZn_yO₄ around x = 0.115

Zero-field muon-spin-relaxation (μSR) measurements have been carried out in order to investigate the effect of nonmagnetic impurities on the dynamics of the Cu-spin fluctuations in the Zn-substituted La_2-xSr_xCu_1-yZn_yO₄ with x=0.115 and 0.13, changing y from 0 to 0.10. A long-range-ordered state of Cu spins, which is observed in the Zn-free sample with x=0.115, disappears in the Zn-free sample with x = 0.13, but appears again in the Zn-substituted samples with x = 0.13 for y ≥ 0.0075. The long-range-ordered state disappears for y > 0.03 for both values of x, so that the Cu spins are in a paramagnetic state. The present μSR results support the suggestion that a small amount of nonmagnetic impurities produces a pinning of the dynamical stripe correlations of spins and holes and make them statically stabilized, while a large amount of nonmagnetic impurities destroy the stripe correlations themselves.