Ionic Conductivity and Magnesium Vacancy Mobility in Magnesium Oxide

Sempolinski, D. R.; Kingery, W. D.

doi:10.1111/j.1151-2916.1980.tb09857.x

Cited by 110 publications

(41 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Table 3 compares the results with the previous experimental and theoretical studies. The activation energy estimated by Sempolinski and Kingery (1980) from ionic conductivity in MgO and theoretical studies (Ammann et al 2011;Ita and Cohen 1997;Ito and Toriumi 2007) agrees reasonably well with this study. Also the activation volume of vacancy migration obtained in the numerical simulations (Ammann et al 2011;Ita and Cohen 1997;Ito and Toriumi 2007) agrees well with this study.…”

Section: Vacancy Diffusivitysupporting

confidence: 84%

The influence of ferric iron and hydrogen on Fe–Mg interdiffusion in ferropericlase ((Mg,Fe)O) in the lower mantle

Otsuka

Karato

2014

Phys Chem Minerals

View full text Add to dashboard Cite

are reasonably consistent with values estimated from previous experimental and theoretical studies.Abstract Both ferric iron (Fe 3+ ) and hydrogen (H + ) have important influence on several transport properties of minerals such as diffusion. We determined the influence of Fe 3+ and H + on Fe-Mg interdiffusion in (Mg,Fe) O at 1,673-1,873 K and 5-24 GPa under the anhydrous and hydrous conditions using the diffusion couple technique. The diffusion couples consist of single crystals of ferropericlase ((Mg,Fe)O) and periclase (MgO) with Mg/ (Mg + Fe) ratios ranging from 0.44 to 1.0. The oxygen fugacity was controlled by the following assemblages of metal and oxide: Fe-FeO, Ni-NiO, Mo-MoO 2 , and ReReO 2 . After the diffusion experiments, hydrogen (H + ) concentrations were measured using the FTIR spectroscopy. Fe 3+ concentrations were measured using the flank method. Under the conditions investigated, Fe-Mg interdiffusivity increases strongly with Fe 3+ and modestly with H + and the influence of H + relative to that of Fe 3+ on Fe-Mg interdiffusion decreases with temperature. Our results show that, under both anhydrous and hydrous conditions, the dominant defect responsible for diffusion is the same suggesting that H + enhances Fe-Mg interdiffusivity by enhancing the mobility of vacancies at the M-site. Our results indicate that the influence of Fe 3+ likely dominates at temperatures expected for the normal lower mantle conditions (T > 1,900 K), while the influence of both Fe 3+ and H + is important at lower temperature environments such as near the subduction zone. We also estimated the vacancy diffusivity based on Fe-Mg interdiffusion and vacancy concentration estimated from the charge neutrality condition with Fe 3+ . Both Fe-Mg interdiffusivity and vacancy diffusivities

show abstract

Section: Vacancy Diffusivitysupporting

confidence: 84%

The influence of ferric iron and hydrogen on Fe–Mg interdiffusion in ferropericlase ((Mg,Fe)O) in the lower mantle

Otsuka

Karato

2014

Phys Chem Minerals

View full text Add to dashboard Cite

show abstract

“…Table 1 compares H m * with the activation enthalpies of three experimental [ Sempolinsky and Kingery , 1980; Ando et al , 1983; Yang and Flynn , 1994] and one theoretical study [ Ita and Cohen , 1997]. Table 1 also compares formation enthalpies ( H f * ) given by the total energy differences of perfect and vacancy containing crystals.…”

Section: Resultsmentioning

confidence: 99%

Pressure effect of self‐diffusion in periclase (MgO) by molecular dynamics

Ito

Toriumi

2007

J. Geophys. Res.

View full text Add to dashboard Cite

[1] Pressure effect of self-diffusion in periclase (MgO) was investigated by molecular dynamics (MD), and viscosity variation of lower mantle periclase was predicted by employing the Nabarro-Herring model. Self-diffusion coefficients were derived directly from recorded trajectories of atoms. The MD calculations were performed at 2400-6000 K and 0-140 GPa. Migration energy (H m * ) and formation energy (H f * ) of ordinary pressure (0 GPa) are consistent with experimental data. Observed pressure dependence of self-diffusion coefficients was turned from negative with increasing pressure. The behavior of self-diffusion coefficients predicts softening of lower mantle periclase with increasing depth. We predict 1.3 times reduction of the viscosity (0.3 K/km geothermal gradient) or 2.0 times (0.6 K/km geothermal gradient).Citation: Ito, Y., and M. Toriumi (2007), Pressure effect of self-diffusion in periclase (MgO) by molecular dynamics, J. Geophys.

show abstract

“…An alternative, large-polaron mechanism has been observed in pure periclase [Sempolinski et al, 1980] …”

Section: Previous Measurements Of Magnesiowtistite Conductivitymentioning

confidence: 99%

The electrical conductivity of the lower mantle phase magnesiowüstite at high temperatures and pressures

Dobson¹,

Brodholt²

2000

J. Geophys. Res.

View full text Add to dashboard Cite

show abstract

Ionic Conductivity and Magnesium Vacancy Mobility in Magnesium Oxide

Cited by 110 publications

References 20 publications

The influence of ferric iron and hydrogen on Fe–Mg interdiffusion in ferropericlase ((Mg,Fe)O) in the lower mantle

The influence of ferric iron and hydrogen on Fe–Mg interdiffusion in ferropericlase ((Mg,Fe)O) in the lower mantle

Pressure effect of self‐diffusion in periclase (MgO) by molecular dynamics

The electrical conductivity of the lower mantle phase magnesiowüstite at high temperatures and pressures

Contact Info

Product

Resources

About