Abstract
It is reviewed that how the excess heat capacity observed in supeitonic conductors is concerned with its structure and the behaviour of mobile ions distributed in a highly disordered fashion. Superionic conductors are classified into two types according to the number of ions responsible to ionic conduction; in Type I, all ions of one specy in the compound are responsible, such as α-AgI, and in Type II, mobile ions are produced by doping an impurity into insulators and are equal to the number of the impurity introduced, such as YSZ (ZrO2+Y2O3). The crystal structure and the heat capacity of the Type I supeitonic conductors are mainly described, especially on α-AgI, α-Ag2S, and α-RbAg4I5.
