Quasi-elastic and inelastic neutron-scattering studies of superconducting La2−xSrxCuO4

We review the results of recent neutron-scattering studies of the spin fluctuations in samples of La
1.89
Sr
0.11
CuO
4
which are ∼80% superconducting with T
c
= 10 K. The structure factor, S(Q̄), reflects three-dimensional modulated spin correlations with an in-plane correlation length of order 18 ± 6 Å. The fluctuations evolve with temperature from being predominantly dynamic at high temperatures to mainly quasi-elastic (|ΔE| < 0.5 meV) at low temperatures. No significant differences are observed in the normal and superconducting states.