Thermoelectric power of the superionic conductors Ag4MI5(M=K and Rb)

Abstract

The thermoelectric power ( theta ) of Ag₄KI₅and Ag₄RbI₅is measured between room temperature and few degrees below their melting points using silver electrodes. The behaviour of theta with temperature can be expressed by the equations - theta =0.088(10³/T)+0.310(mVK^-1), (40-240 degrees C) and - theta =0.086(10³/T)+0.338(mVK^-1), (40-225 degrees C) respectively, for the two solids. A theoretical analysis of the data gives 0.088 and 0.086 eV for the heats of transport of Ag⁺ions which are very close to the respective activation energies, in accordance with the prediction of the free-ion theory of Rice and Roth (1972) as well as that of the earlier theory on the heats of transport.