Magnetic fluctuations in La1.95Ba0.05CuO4

Abstract

Neutron-scattering and resistivity experiments on single crystals of ${\mathrm{La}}_{1.95}$ ${\mathrm{Ba}}_{0.05}$ ${\mathrm{CuO}}_4$ are described. On warming to as high as 250 K, the correlation length does not change, and the temperature dependence of the generalized susceptibility χ(Q,ω) is due solely to the temperature-dependence of the local response. We show that the associated relaxation rate in the metallic regime is ħΓ≃1/2${\mathit{k}}_{\mathit{B}}$T, in accord with the marginal-Fermi-liquid hypothesis, and relate our results to nuclear spin-lattice relaxation data.