Field-cooled and zero-field-cooled dielectric susceptibility in deuteron glasses

The temperature dependence of the field-cooled and zero-field cooled static dielectric susceptibilities of the deuteron glass ${\mathrm{Rb}}_{0.4}$(${\mathrm{ND}}_4$ ${)}_{0.6}$ ${\mathrm{D}}_2$ ${\mathrm{PO}}_4$ has been determined. Whereas above the freezing temperature ${\mathit{T}}_{\mathit{f}}$ the two susceptibilities are equal, a splitting of the two branches as well as a remanent polarization is observed below ${\mathit{T}}_{\mathit{f}}$. The fact that this splitting takes place demonstrates the occurrence of a freezing transition on crossing the Almeida-Thouless-like line.