Two-dimensional spin fluctuations in Sr2RuO4

We report inelastic neutron scattering measurements carried out on single crystals of Sr2RuO4 in the normal state. The results are in agreement with band structure calculations that predict a sizable magnetic response at the incommensurate wave vector qo=(±2π/3a,±2π/3a,0), as expected from the nesting properties of the Fermi surface. The incommensurate spin fluctuations have been investigated mainly within the (a,b)-plane over a wide range of energies. Additional measurements along the c-axis shows that the magnetic correlations are two-dimensional.