Inelastic neutron scattering study of the magnetic fluctuations in   Sr$_2$RuO$_4$
  By performing time-of-flight neutron scattering measurements on a large amount of single crystals of Sr$_2$RuO$_4$, we studied detailed structure of the imaginary part of the dynamic spin susceptibility over a wide range of phase space. In the normal state at T=5 K, strong incommensurate (IC) peaks were clearly observed at around $\mathbf{Q}_\text{c}=(0.3,0.3)$ up to at least $\hbar\omega=80$ meV. In addition, our data also show strong magnetic fluctuations that exist on the ridges connecting the IC peaks around the $(\pi,\pi)$ point rather than around the $\Gamma$ point. Our results are consistent with the semi-mean-field random phase approximation calculation for a two dimensional Fermi liquid with a characteristic energy of 5.0 meV. Furthermore, the IC fluctuations were observed even at room temperature. 
K. Iida, M. Kofu, N. Katayama, J. Lee, R. Kajimoto, Y. Inamura, M.   Nakamura, M. Arai, Y. Yoshida, M. Fujita, K. Yamada, S....
cond-mat.str-el