Neutron-scattering study of spin correlations in electron-doped Pr0.89LaCe0.11CuO4 single crystals

We have performed neutron-scattering measurements on the single crystals of electron-doped cuprate, Pr-0.89-LaCe0.11CuO4-delta in order to study the relationship between spin correlations and the superconductivity. In the non-superconducting as-grown x = 0.11 sample, clear magnetic Bragg peak appears below 200 K, while no evidence of antiferromagnetic order was found in the oxygen-reduced superconducting one (T-c = 25.5 K). These results imply that superconductivity concomitantly appears with the degradation of a magnetic ordering by oxygen-reduced procedure. Furthermore, we observed clear commensurate low-energy spin fluctuations, at the antiferromagnetic zone center in both as-grown and reduced samples, analogous to the result for Nd1.85Ce0.15CuO4. Therefore, commensurate spin fluctuations are robust against the electron-doping and is commonly exist in the electron-doped superconductors. (C) 2003 Elsevier B.V. All rights reserved.