Low-energy vibrations in superionic glasses

Measurements of low temperature specific heat C p (1.5 K-25 K) have been carried out in AgI-Ag 2 O-B 2 O 3 superionic glasses. It has been revealed that modifications of the network coherence change the magnitude of the hump in the specific heat, which is observed when it is plotted as C p /T 3 : the increasing connectivity (defined as the number of bridging bonds per network forming ion) reduces the deviations of C p from a T 3 behavior. Finally comparative measurements of low temperature C p and low frequency Raman scattering (below 100 cm -1 ) in the same glass permit us to assess the frequency dependence of the photon-vibration coupling coefficient C(ω) and the spectral density of low-energy vibrational modes g(ω).