Electrical Conductivity of Single Crystals of MgO

Abstract

The electrical conductivity of magnesium oxide at temperatures in the region of 1300°C is observed to depend upon the partial pressure of oxygen surrounding the sample. The conductivity increases at oxygen pressures both higher and lower than 10-5 atmospheres. At this pressure the conductivity is a minimum. This effect is increased as the iron content is increased and is almost absent in the purest samples.The conductivity is electronic rather than ionic and the number of charge carriers is controlled by the number of lattice vacancies. The dependence of conductivity on oxygen pressure may be satisfactorily explained by changes in stoichiometry and thus lattice defects in magnesium oxide. These changes in stoichiometry are larger when the magnesium oxide is contaminated with a variable valence impurity like iron than when it is pure.

Temperature variation at constant pressures of the electrical conductivity of periclase and olivine

“…Evidence that platinum foil, which was used here, is a satisfactory electrode material comes from the similarity of conductivity values found by Miroff [1959] for MgO using two-probe and four-probe measuring techniques.…”

Highly defective MgO nanosheets from colloidal self-assembly

“…The high dielectric constant and conductivity indicate a strongly thermally activated charge mobility, which reaches a maximal conductivity of $6 Â 10 À9 S m À1 at 470 K which is almost 3 orders of magnitude greater than the bulk value. 30,31 The dielectric constant was about 30 times higher than the bulk value. 32 A relatively low charge delocalization energy barrier of $300 meV was estimated from an Arrhenius fit of the temperature dependence of the conductivity peak frequency.…”

Concentration of Vacancies at Metal-Oxide Surfaces: Case Study of MgO(100)

“…Although the experimental band gap of MgO is 7.8 eV [5], realistic samples are typically neither clear transparent nor insulating. Defects such as intrinsic point defects, impurities, and defect complexes can give rise to electron or hole conductivity [1,6,7]. In the following, we neglect defect complexes (e.g., dopant plus vacancy).…”

“…(7) is to replace the band bending contribution to the formation energy calculated for z SC ¼ d with the one obtained for the actual z SC from Eq. (6). The remaining dependence on after subtracting qE SC ð; dÞ from G VCA;q f ð; dÞ is due to the electrostatic attraction between defect and compensating charge.…”