Spin and charge inhomogeneities in high-T_c cuprates: Evidence from NMR and neutron scattering experiments

In this communication we consider the doping dependence of the strong antiferromagnetic spin fluctuations in the cuprate superconductors. We investigate the effect of an incommensurate magnetic response, as recently observed in inelastic neutron scattering (INS) experiments on several YBa_2Cu_3O_{6+x} compounds, on the spin-lattice and spin-echo relaxation rates measured in nuclear magnetic resonance (NMR) experiments. We conclude that a consistent theoretical description of INS and NMR can be reached if one assumes spatially inhomogeneous but locally commensurate spin correlations and that NMR and INS experiments can be described within a single theoretical scenario. We discuss a simple scenario of spin and charge inhomogeneities which includes the main physical ingredients required for consistency with experiments.