Wednesday, May 29, 2013

1305.6363 (Solène Guitteny et al.)

Anisotropic propagative excitations and quadrupolar effects in
Tb$_2$Ti$_2$O$_7$
   [PDF]

Solène Guitteny, Julien Robert, Jacques Ollivier, Pierre Bonville, Claudia Decorse, Paul Steffens, Martin Boehm, Hannu Mutka, Isabelle Mirebeau, Sylvain Petit
We investigate the dynamical magnetic correlations in \tbti\, using polarized inelastic neutron scattering. Our results provide experimental evidence for dispersive excitations 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, are stiff enough to allow the propagation of collective excitations. They also highlight a strong spin-lattice coupling which is likely driven by interactions between the $4f$ quadrupolar moments.
View original: http://arxiv.org/abs/1305.6363

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