Pressure dependence of proton glass freezing in Rb1−x(NH4)xH2PO4

Abstract

Studies of the frequency-dependent dielectric properties of a ${\mathrm{Rb}}_{0.52}$ ${\left({\mathrm{ND}}_4\right)}_{0.48}$ ${\mathrm{D}}_2$P${\mathrm{O}}_4$ (72% deuterated) crystal have shown that the deuteron glass-freezing temperature $T_g$ is suppressed by hydrostatic pressure at a rate of -2.0 K/kbar. This is explained in terms of the influence of pressure on the hydrogen-bond potential. It is suggested that the glassy state should be completely suppressed (i.e., $T_g\to 0$ K) at a pressure of less than 10 kbar in undeuterated crystals of similar composition.