Neutron-scattering study of static antiferromagnetic correlations in La2-xSrxCu1-yZnyO4

Neutron-scattering measurements have been performed to search for possible elastic incommensurate magnetic peaks in superconducting La2-xSrxCuO4 with x=0.10, 0.12, and 0.15. The most dramatic effects are found for x=0.12; in this case, the peak intensity first appears at the onset of superconductivity T-c (=31 K). The resolution-limited peak width indicates that the static magnetic correlation length exceeds 200 Angstrom isotropically in the CuO2 planes. Weak elastic peaks are also observed at low temperatures for x=0.10 while for x = 0.15 any incommensurate elastic scattering is below the limit of detectability. Elastic peaks are observed in Zn-substituted nonsuperconducting La1.88Sr0.12Cu0.97Zn0.03O4 However, in this case, the Zn substitution degrades the magnetic order; the peak appears at lower temperature (17 K) and the correlation length is shorter (80 Angstrom) than that in the Zn-free x = 0.12 sample. [S0163-1829(99)02909-4].