Anisotropic Propagating Excitations and Quadrupolar Effects in Tb 2 Ti 2 O 7

Solène Guitteny (1) , Julien Robert (1) , Pierre Bonville (2) , Jacques Ollivier (3) , Claudia Decorse (4) , Paul Steffens (3) , Martin Boehm (3) , Hannu Mutka (3) , Isabelle Mirebeau (1) , Sylvain Petit (1)

1 LLB - UMR 12 - Laboratoire Léon Brillouin
2 LNO - Laboratoire Nano-Magnétisme et Oxydes
3 ILL - Institut Laue-Langevin
4 CHIMSOL - Laboratoire de Physico-Chimie de l'Etat Solide

The dynamical magnetic correlations in Tb2Ti2O7 have been investigated using polarized inelastic neutron scattering. Dispersive excitations are observed, emerging from pinch points in reciprocal space and characterized by an anisotropic spectral weight. Anomalies in the crystal field and phonon excitation spectrum at Brillouin zone centers are also reported. These findings suggest that Coulomb phases, although they present a disordered ground state with dipolar correlations, allow the propagation of collective excitations. They also point out a strong spin-lattice coupling, which likely drives effective interactions between the 4f quadrupolar moments.

Domaines: Physique [physics]

Solène Guitteny, Julien Robert, Pierre Bonville, Jacques Ollivier, Claudia Decorse, et al.. Anisotropic Propagating Excitations and Quadrupolar Effects in Tb 2 Ti 2 O 7. Physical Review Letters, 2013, 111 (8), ⟨10.1103/PhysRevLett.111.087201⟩. ⟨cea-01477940⟩