Superionic-protonic behavior of a new mixed sodium dihydrogen phosphate-arsenate at room temperature

The elaborate mixed material of the formula NaH2(PO4)0.48(AsO4)0.52·H2O denoted by NDAP belongs to a group of compounds having properties that are intermediate between those of a normal salt and an acid, and undergoes a transition from a paraelectric to a superprotonic phase transition at room temperature. The temperature phase transition (296 K) leading to a superionic-protonic phase characterized by an unusual high conductivity at room temperature was found. The conductivity relaxation parameters associated with the high-disorder protonic conduction have been determined from the analysis of the M″/M″max spectrum and measured in a wide temperature range. Transport properties in this material appear to be due to proton hopping mechanism.