Vogel-fulcher scaling of the susceptibility in a mixed-crystal proton glass

Low-temperature dispersion of the electric susceptibilities in a mixed crystal of Rb1-x(NH4)xH2PO4 (x=0.35) is reported. The frustrated proton ordering of this system relates it to spin-glasses. The measurements reveal a broad distribution of relaxation times. The data scale using a temperature-independent distribution of activation energies linked to the relaxation times by a Vogel-Fulcher law with a freezing temperature of 10 K. © 1983 The American Physical Society.