Using Cu nuclear quadrupole resonance (NQR) in Eu-doped ${\mathrm{La}}_{2-x}{\mathrm{Sr}}_x{\mathrm{CuO}}_4$ we find the evidence of the pinned stripe phase at 1.3 K for $0.08\le x\le 0.18$. The pinned fraction increases by 1 order of magnitude near hole doping $x=1\mathrm{}/8$. The NQR line shape reveals three inequivalent Cu positions: (i) sites in the charged stripe, (ii) nonmagnetic sites outside the stripes, and (iii) sites with a magnetic moment of $0.29{\mu }_B$ in the antiferromagnetically correlated regions. A dramatic change of the NQR signal for $x>\mathrm{}0.18\mathrm{}$ correlating with the onset of bulk superconductivity corresponds to the depinning of the stripe phase.

• Received 4 October 1999

DOI:https://doi.org/10.1103/PhysRevLett.84.2949