Electrical conductivity of gabbro: the effects of temperature, pressure and oxygen fugacity

Abstract

The electrical conductivity of gabbro was investigated at 623–1173 K, 0.5–2.0 GPa and oxygen fugacities controlled by three solid buffers (Cu + CuO, Ni + NiO and Mo + MoO 2 ) using a YJ-3000t multianvil press and Solartron-1260 impedance spectroscopy analyzer within the frequency range 10 −1 –10 6 Hz. The measured electrical conductivity shows an Arrhenius increase with temperature and increases with increasing pressure. The activation energy and activation volume of charge carriers have been determined as 0.72±0.01 eV and −6.8 ± 0.69 cm 3 /mol, respectively. The hydrogen-assisted electrical conductivity in gabbro decreases with increasing oxygen fugacity. Furthermore, it is inferred that some hydrogen-related defects with minor concentration ( e.g ., H′ M or H • ) are the main charge carriers in the sample and provide reasonable explanations for the behavior of electrical conductivity of gabbro at high pressure.