  The nature of the unconventional ordered phase occurring in CeRu2Al10 below
T0 = 27 K was investigated by neutron scattering. Powder diffraction patterns
show clear superstructure peaks corresponding to forbidden (h + k)-odd
reflections of the Cmcm space group. Inelastic neutron scattering experiments
further reveal a pronounced magnetic excitation developing in the ordered phase
at an energy of 8 meV.
