Electrical Conductivity of Uranium Dioxide

The electrical conductivity of nearly stoichiometric single‐crystal and polycrystalline uranium dioxide was measured from room temperature to 3000°K. Below approximately 550°K, the curve of log σ versus T −1 is linear with a calculated activation energy of approximately 0.17 ev. Between 550° and 1250°K, however, the shape of the curve changes; this change varies from one specimen to another. The electrical conductivity increases rapidly with increasing temperature above 1250°K with a change from p ‐type to n ‐type conduction. The best linear fit of the log σ versus T −1 curve above 1400°K is σ= 3.57 × 10 3 e −(1.15 ev/KT) . Above 1900°K, the curve deviates slightly from linearity and is best fit by the equation σ= 2.10 × 10 −2 T 1.4 e −(0.916 ev/KT) .