Optical in-situ spectroscopy of high-temperature properties of olivines

Abstract

Abstract An in-situ optical spectroscopy investigation at high temperatures is reported into the defect chemistry and cation kinetics of cobalt-containing olivines. The equilibrium defect optical absorption is studied as a function of oxygen activity at high temperatures. The kinetics of cation redistribution between the two non-equivalent sites in the olivine crystal structure is investigated by temperature-jump relaxation experiments. It is found that both the compositional dependence of kinetics of the cation redistribution process and the dependence of point defect concentration on oxygen activity favor a defect model involving cation vacancies and electron holes (Co3+).