title: Anisotropic exchange in frustrated pyrochlore Yb(2)Ti(2)O(7).
abstract: The local Yb(3+) magnetic susceptibility tensor was recently measured in the frustrated pyrochlore compound Yb(2)Ti(2)O(7) by means of in-field polarized neutron scattering in a single crystal. A very anisotropic effective exchange tensor was derived for the Yb(3+) ion. Using this result, we reinterpret here the data for the powder susceptibility in Yb(2)Ti(2)O(7). We show that, in the case of a well-isolated Kramers doublet with anisotropic g and exchange tensors, the inverse susceptibility for a powder sample does not strictly obey a Curie-Weiss law at low temperature. We discuss the consequences regarding the paramagnetic Curie temperature, usually taken as a measure of the exchange/dipolar interaction, and the exotic 'slow fluctuation' ground state of Yb(2)Ti(2)O(7).
authors.affiliation: CEA, Centre de Saclay, Laboratoire Léon Brillouin, F-91191 Gif-sur-Yvette, France.
authors.forename: H B
authors.initials: HB
authors.lastname: Cao
authors.forename: A
authors.initials: A
authors.lastname: Gukasov
authors.forename: I
authors.initials: I
authors.lastname: Mirebeau
authors.forename: P
authors.initials: P
authors.lastname: Bonville