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A high-temperature electrical conduction mechanism in the lower mantle phase (Mg,Fe)1-xO
Ist Teil von
Science (American Association for the Advancement of Science), 1997-03, Vol.275 (5307), p.1779-1781
Ort / Verlag
Washington, DC: American Association for the Advancement of Science
Erscheinungsjahr
1997
Link zum Volltext
Quelle
American Association for the Advancement of Science
Beschreibungen/Notizen
Measurements of electrical conductivity at high pressure and temperature were taken on the lower mantle phase magnesiowustite with varying Fe3+ content. Although previous measurements at atmospheric pressure suggest Fe2+-Fe3+ hopping (small polaron) as the dominant conductivity mechanism, the present experiments show a change in charge transport mechanism with temperature. The lower temperature measurements are consistent with small polaron conduction, but at higher temperatures, which are more applicable to the lower mantle, a large polaron mechanism is suggested. Because these mechanisms have different temperature and compositional dependencies, this transition has important implications for extrapolation to mantle conditions.