Spin Dynamics and Orbital State in LaTiO_3
  A neutron scattering study of the Mott-Hubbard insulator LaTiO$_{3}$ (T$_{{\rm N}}=132$ K) reveals a spin wave spectrum that is well described by a nearest-neighbor superexchange constant $J=15.5$ meV and a small Dzyaloshinskii-Moriya interaction ($D=1.1$ meV). The nearly isotropic spin wave spectrum is surprising in view of the absence of a static Jahn-Teller distortion that could quench the orbital angular momentum, and it may indicate strong orbital fluctuations. A resonant x-ray scattering study has uncovered no evidence of orbital order in LaTiO$_{3}$. 
B. Keimer, D. Casa, A. Ivanov, J.W. Lynn, M. v. Zimmermann, J.P. Hill,   D. Gibbs, Y. Taguchi, and Y. Tokura