Electrical Conductivity of Near-Stoichiometric α-Nb2O5 in the Temperature Range 900° to 1400°C

Abstract

The electrical conductivity of near‐stoichiometric α‐Nb₂O₅ was measured in the temperature range 900° to 1400°C and at oxygen pressures between 1 and 0.005 atm. Over this entire range the change in conductivity with oxygen pressure is in accord with the relation σ∝Po₂^—¼. From the exponential temperature dependence of conductivity in the range 1400° to 700°C an activation energy of 1.65 eV can be calculated. These results are in excellent agreement with previous investigators who obtained the same relationships in the temperature range 600° to 900°C. Therefore, it is felt that the conduction process is controlled by a single mechanism over the temperature range 700° to 1400°C at oxygen pressures between 1 atm to 0.005. From mass‐action considerations it is postulated that the mechanism responsible is probably the excitation of the first electron from an oxygen ion vacancy which has trapped two electrons.