Static and dynamic spin fluctuations in the spin glass doping regime in La 2−xSr xCuO 4+δ

Abstract

We review the results of neutron scattering studies of the static and dynamic spin fluctuations in crystals of La 2− x Sr x CuO 4+δ in the doping regime intermediate between the Néel and superconducting regions. In this regime the in-plane resistance is linear in temperature down to ω80 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 K( x,T= K( x,0)+ K(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 ω/ T for temperatures 10 K ⩽ T⩽500K for a wide range of energies. This scaling leads to a natural explanation of a variety of normal state properties of the copper oxides.