STATIC AND DYNAMIC SPIN FLUCTUATIONS IN THE SPIN-GLASS DOPING REGIME IN LA2-XSRXCUO4+DELTA

We review the results of neutron scattering studies of the static and dynamic spin fluctuations in crystals ot La2-xSrxCuO4+delta in the doping regime intermediate between the Neel and superconducting regions. In this regime thc in-plane resistance is linear in temperature down to approximately 80 K with a crossover due to logarithmic conductance effects at lower temperatures. The static spin correlations are well described by a simple model in which the inverse correlation length kappa(x, T) = kappa(x, 0) + kappa(0, T). The most dramatic new result is the discovery by Keimer et al. that the dynamic spin fluctuations exhibit a temperature dependence which is a simple function of omega/T for temperatures 10 K less-than-or-equal-to T less-than-or-equal-to 500 K for a wide range of energies. This scaling leads to a natural explanation of a variety of normal state properties of the copper oxides.