OBSERVATION OF COLLECTIVE EXCITATIONS IN THE AMORPHOUS ALLOY NI67ZR33

The dynamical structure factor, S(Q, E), for the amorphous alloy Ni67Z r33 has been measured by neutron inelastic scattering, over a wide ran ge of momentum, Ae, and energy transfer, E. The collective character o f the excitations, i.e. a dispersion relation, is observed up to Q=9 A ngstrom(-1), which is the:limit accessible in the present experiment. For the amorphous alloy Ni67Zr33, it is first experimental proof that the dispersion curve oscillates and damps around a mean value of the e xcitation energy (21 meV). (C) 1998 Elsevier Science B.V. All rights r eserved.