中国科学院地球化学研究所机构知识库

At 1.0–4.0 GPa and 11213–1473 K and under oxygen fugacity-controlled conditions (Bi + NiO, Fe + Fe3O4, Fe + FeO and Mo + MoO2 buffers), a YJ-3000t Model six-anvil solid high-pressure apparatus and a Sarltron-1260 Impedance/Gain-Phase analyzer were employed to conduct an in situ measurement of the electrical conductivity of single crystal olivine. Experimental results showed that: (1) within the range of experimentally selected frequencies (10³–10⁶ Hz), the electrical conductivity of the sample is of great dependence on the frequency; (2) with the rise of temperature (T); the electrical conductivity (σ) will increase, and the Arrenhius linear relationship is established between 1gσ and 1/T; (3) under the control of oxygen buffer Fe + Fe3O4, with the rise of pressure, the electrical conductivity tends to decrease whereas the activation enthalpy and independent-of-temperature preexponential factor tend to increase, with the activation energy and activation volume of the sample estimated at (1.25 + 0.08) eV and (0.14058 + 0.025) cm³/mol, respectively; (4) under given pressure and temperature conditions, the electrical conductivity tends to increase whereas the activation energy tends to decrease with increasing oxygen fugacity; and (5) the mechanism of electrical conduction of small polarons can provide insight into the behavior of electrical conduction of olivine under high pressure and high temperature.