Transport properties of Usub(0.7)Cesub(0.3)Osub(2-x)

We have determined a number of transport properties of Usub(0.7)Cesub(0.3)Osub(2-x) at 1273 K for various deviations from stoichiometry and compared them with available results on (UPu)Osub(2-x). They are: the electrical conductivity, Seebeck coefficient, effective charge number and chemical diffusion coefficient. A very characteristic behaviour is observed for the electronic properties of (UCe)Osub(2-x). A p-type conduction for all the studied deviations from stoichiometry (up to x=3x10-2) is interpreted in terms of a high electronic disorder in the stoichiometric compound. Electronic disorder at stoichiometry is probably less important in (UPu)Osub(2-x) which presents a sharp p-n transition at x=5x10-3. Ionic transport properties obtained on (UCe)Osub(2-x) indicate an approximate proportionality between the ionic conductivity resulting from oxygen ions transport and the deviation from stoichiometry. Results available on (UPu)Osub(2-x) do not appear to be compatible with ours and some arguments are presented which cast doubt on their validity. (orig.)