Qdependence of the magnetic response inURu2Si2

We have performed inelastic neutron-scattering experiments with $E_0$=12.7 meV on the superconducting heavy-fermion system ${\mathrm{URu}}_2$ ${\mathrm{Si}}_2$ in the temperature range 5–50 K. The main feature of the magnetic response is an inelastic excitation at a few meV. The intensity of the magnetic scattering shows a ‖Q‖ dependence which we will discuss for temperatures above and below the Néel temperature $T_N$=17.5 K. From the neutron-scattering data one can extract a local magnetic susceptibility, which shows strong spatial correlations even above $T_N$. These correlations are mainly visible in the 〈101〉 direction. The Van Vleck term of the local susceptibility corresponding to the inelastic excitation shows a clear peak at the Néel temperature, in contrast to a weak kink in the static bulk susceptibility.