Study of the Soret effect in mixed conductors by the measurement of ionic and electronic thermopower

The redistribution of a mobile component in a mixed conducting compound A1 + deltaXv in a temperature gradient can be studied by means of time-dependent measurements of either the ionic or the electronic thermovoltage. The reduced heat of transport of the mobile component (QA* or Qx*) results directly from the difference of the partial thermovoltages at t → 0 and t → ∞: For materials with predominant ionic conductivity, the electronic thermopower has to be measured; for materials with predominant electronic conductivity, the ionic thermopower has to be measured. Experimental examples are presented