Keimer B, Casa D, Ivanov A, Lynn JW, von Zimmermann M, Hill JP, Gibbs D, Taguchi Y, Tokura Y
PHYSICAL REVIEW LETTERS
85 (18): 3946-3949 OCT 30 2000
A neutron scattering study of the Mott-Hubbard insulator LaTiO3 (T-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 LaTiO3.