title: Anisotropic propagating excitations and quadrupolar effects in Tb2Ti2O7.
abstract: 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.
authors.affiliation: Laboratoire Léon Brillouin, CEA Saclay, Bâtiment 563, 91191 Gif-sur-Yvette Cedex, France.
authors.forename: Solène
authors.initials: S
authors.lastname: Guitteny
authors.forename: Julien
authors.initials: J
authors.lastname: Robert
authors.forename: Pierre
authors.initials: P
authors.lastname: Bonville
authors.forename: Jacques
authors.initials: J
authors.lastname: Ollivier
authors.forename: Claudia
authors.initials: C
authors.lastname: Decorse
authors.forename: Paul
authors.initials: P
authors.lastname: Steffens
authors.forename: Martin
authors.initials: M
authors.lastname: Boehm
authors.forename: Hannu
authors.initials: H
authors.lastname: Mutka
authors.forename: Isabelle
authors.initials: I
authors.lastname: Mirebeau
authors.forename: Sylvain
authors.initials: S
authors.lastname: Petit