Transport Phenomena in Pure and Doped Magnesium Oxide

Abstract

Ac electrical conductivity measurements have been made on polycrystalline samples of various compositions in the MgO–NiO system. Four activation energies have been obtained with pure MgO: 5.2, 2.7, 3.5, and 0.92 eV. These seem to be the activation energies, respectively, for intrinsic O= conductivity, extrinsic O= conductivity, intrinsic Mg++ conductivity, and extrinsic Mg++ conductivity. Introduction of NiO into the specimens increases the conductivity and decreases the activation energy. The conductivity of the polycrystalline MgO specimens used in this study is larger than literature data for MgO single crystals. This difference results from the large number of grain boundaries present in polycrystals.