TY - JOUR
T1 - Anisotropy of electrical conductivity in dry olivine
AU - Du Frane, Wyatt L.
AU - Roberts, Jeffery J.
AU - Toffelmier, Daniel A.
AU - Tyburczy, James
PY - 2005/12/28
Y1 - 2005/12/28
N2 - The electrical conductivity (σ) was measured for a single crystal of San Carlos olivine (Fo89.1) for all three principal orientations over oxygen fugacities 10-7 < fO2 < 101 Pa at 1100, 1200, and 1300°C. Fe-doped Pt electrodes were used in conjunction with a conservative range of fO2, T, and time to reduce Fe loss resulting in data that is ∼0.15 log units higher in conductivity than previous studies. At 1200°C and fO2) = 10-1 Pa, σ[100] = 10-2.27S/m, σ[010] = 10-2.49S/m, σ[001] = 10-2.40S/m. The dependences of σ on T and fO2 have been simultaneously modeled with undifferentiated mixed conduction of small polarons and Mg vacancies to obtain steady-state fO2-independent activation energies: Ea[100] = 0.32 eV, Ea[010] = 0.56 eV, Ea[100] = 0.71 eV. A single crystal of dry olivine would provide a maximum of ∼100.4 S/m azimuthal σ contrast for T < 1500°C. The anisotropic results are combined to create an isotropic model with Ea = 0.53 eV.
AB - The electrical conductivity (σ) was measured for a single crystal of San Carlos olivine (Fo89.1) for all three principal orientations over oxygen fugacities 10-7 < fO2 < 101 Pa at 1100, 1200, and 1300°C. Fe-doped Pt electrodes were used in conjunction with a conservative range of fO2, T, and time to reduce Fe loss resulting in data that is ∼0.15 log units higher in conductivity than previous studies. At 1200°C and fO2) = 10-1 Pa, σ[100] = 10-2.27S/m, σ[010] = 10-2.49S/m, σ[001] = 10-2.40S/m. The dependences of σ on T and fO2 have been simultaneously modeled with undifferentiated mixed conduction of small polarons and Mg vacancies to obtain steady-state fO2-independent activation energies: Ea[100] = 0.32 eV, Ea[010] = 0.56 eV, Ea[100] = 0.71 eV. A single crystal of dry olivine would provide a maximum of ∼100.4 S/m azimuthal σ contrast for T < 1500°C. The anisotropic results are combined to create an isotropic model with Ea = 0.53 eV.
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U2 - 10.1029/2005GL023879
DO - 10.1029/2005GL023879
M3 - Article
AN - SCOPUS:32644433048
SN - 0094-8276
VL - 32
SP - 1
EP - 4
JO - Geophysical Research Letters
JF - Geophysical Research Letters
IS - 24
ER -