Possibility of an ordered state of spins and holes in single-crystalLa2−xSrxCu1−yZnyO4(x=0.21,y=0and 0.01) studied byμSR

Abstract

Zero-field (ZF) and longitudinal-field (LF) muon spin relaxation $(\ensuremath{\mu}\mathrm{SR})$ measurements have been carried out in the overdoped single crystals of ${\mathrm{La}}_{2\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{Cu}}_{1\ensuremath{-}y}{\mathrm{Zn}}_{y}{\mathrm{O}}_{4}$ with $x=0.21,$ $y=0$ and 0.01. In the case of the Zn-substituted crystal with $x=0.21$ and $y=0.01$ in which the high-${T}_{\mathrm{c}}$ superconductivity is almost suppressed, the ZF- and LF-$\ensuremath{\mu}\mathrm{SR}$ measurements have revealed the existence of a static ordered state of Cu spins at low temperatures below 2 K. No clear coherent precession of the muon spin has been observed down to 20 mK. Slowing down of the Cu-spin fluctuations has also been observed in the non-Zn-substituted crystal with $x=0.21$ and $y=0$ at low temperatures below about 0.8 K in ZF, indicating that the observed magnetic anomaly is an intrinsic property at $x=0.21.$ These $\ensuremath{\mu}\mathrm{SR}$ results suggest a strong possibility of the existence of a spin/charge ordered state at $x=0.21$ in the overdoped region.