Crystal field parameters of the rare earth pyrochlores $R_2$Ti$_2$O$_7$   ($R$ = Tb, Dy, Ho)
  In this work we present inelastic neutron scattering experiments which probe the single ion ground states of the rare earth pyrochlores $R_2$Ti$_2$O$_7$ ($R$ = Tb, Dy, Ho). Dy$_2$Ti$_2$O$_7$ and Ho$_2$Ti$_2$O$_7$ are dipolar spin ices, now often described as hosts of emergent magnetic monopole excitations; the low temperature state of Tb$_2$Ti$_2$O$_7$ has features of both spin liquids and spin glasses, and strong magnetoelastic coupling. We measured the crystal field excitations of all three compounds and obtained a unified set of crystal field parameters. Additional measurements of a single crystal of Tb$_2$Ti$_2$O$_7$ clarified the assignment of the crystal field levels in this material and also revealed a new example of a bound state between a crystal field level and an optical phonon mode. 
M Ruminy, E Pomjakushina, K Iida, K Kamazawa, D T Adroja, U Stuhr, T   Fennell
cond-mat.mtrl-sci cond-mat.other