Effect of pressure on conductivity in liquid and glassy states of a superionic conducting glass

To observe whether pressure acting on the liquid state of a fast ion conducting vitreous solid electrolyte has a very different effect from pressure acting on the fixed structure vitreous state, measurements have been performed on (AgI)₄₀(AgPO₃)₆₀ over a range of pressures and temperatures. Below T_g, conductivity decreases according to classic transition state theory expressions with volume of activation close to the mobile ion volume. Pressure applied near and above T_g has only a slightly different effect than the same pressure applied well below T_g below, in contrast to the pressure effect on viscosity above T_g. An explanation links weak pressure effects to previously known weak quenching (fictive temperature) effects, through the high decoupling index.