PRESSURE-DEPENDENCE OF THE ELECTRICAL-CONDUCTIVITY OF (MG0.9FE0.1)SIO3 PEROVSKITE

The electrical conductivity of (Mg0.9Fe0.1)SiO3 perovskite has been measured at pressures of 0-8 GPa and ambient temperature using a DIA-6 cubic-anvil apparatus. At ambient conditions, the electrical conductivity of the (Mg0.9Fe0.1)SiO3 perovskite is found to be 7.6 (+/-2.0) x 10(-9) S/m. The conductivity of the perovskite increases with increasing pressure, and the activation volume for electrical conduction is determined to be -0.12 (+/-0.04) cm3/mol. As a cross-check with previous electrical conductivity measurements, an assemblage of the perovskite and magnesiowustite synthesized from the (Mg0.89Fe0.11)2SiO4 olivine has been examined in the present study using a laser-heated diamond anvil cell at approximately 48 GPa and in the temperature range of 295-3500 K. The results for this assemblage are consistent with those for the pure (Mg0.9Fe0.1)SiO3 perovskite. The present experimental data show that the electrical conductivity of the crystalline (Mg0.9Fe0.1)SiO3 perovskite remains below 10(-5) S/m at 300 k and lower mantle pressures.