Conductivity study of a new protonic conductor Rb1.12(NH4)0.88SO4·Te(OH)6

Single crystals of Rb1.12(NH4)0.88SO4·Te(OH)6 were obtained by slow evaporation at 300 K. Differential scanning calorimetry showed an anomaly at 418 K, two shoulders at 482 and 510 K and one strong peak at 517 K. X-ray diffraction shows that the first DSC peak at 418 K passes the material from paraelectric to ferroelectric phase. A conductivity study shows that the shoulder at 482 (which masks a second one at about 458 K) can be attributed to a superprotonic phase transition. Dielectric constant and dissipation factor evolutions indicate that the peak at 458 K is probably due to a ferroelectric–paraelectric phase transition. The strong peak at 517 K was attributed to the decomposition of the salt.