MAGNETIC AND TRANSPORT-PROPERTIES OF CE2 3TIO2.981/

The transport and magnetic properties of A-site-deficient Ce2/3TiO2.98 1 perovskite have been investigated. The electrical conductivity displ ayed a thermally activated temperature dependence between 200 and 300 K with an activation energy of 0.17 eV. The thermopower measured over a similar temperature range showed little temperature dependence, indi cating that transport occurs by means of coupling between localized le vels. Analysis of the susceptibility based on the Curie-Weiss law indi cated that the Curie constant of the 4f spin of Ce is approximately 40 % smaller than that of the free ion due to the crystalline-electric-fi eld effects. Unlike CeTiO3, Ce2/3TiO2.981 shows a very simple temperat ure dependence of its magnetic susceptibility and there is no evidence for the onset of weak ferromagnetism at any temperature. These result s are shown to be consistent with transport by means of adiabatic hopp ing of small polarons.