Fast proton-conducting Mg(PO3)2 glasses were obtained by the implantation of 120keV protons to a fluence of 1018/cm2. The direct-current room temperature conductivity and activation energy for conduction in the implanted glasses were 0.0005S/cm and 0.18eV, respectively. No fast proton conduction was observed in H+-implanted SiO2 or Ca(PO3)2 glasses. Infra-red absorption spectra revealed that the implanted protons were present in the form of Si-OH or P-OH in SiO2 and Ca(PO3)2 glasses which had been implanted with H+ ions to 1018/cm2, but existed as POH groups and molecular water in Mg(PO3)2 glasses. It was concluded that the coexistence of acidic groups, such as POH and H2O, was a structural requirement for the appearance of fast proton conduction in oxide glasses. The formation of H2O in Mg(PO3)2 was explained by considering its thermodynamic stability with regard to SiO2 and Ca(PO3)2 glasses.

H.Hosono, K.Kawamura, H.Kawazoe, N.Matsunami, Y.Abe: Journal of Applied Physics, 1997, 81[3], 1296-301