Generation of pressures to 60 GPa in Kawai-type apparatus and stability of MnGeO3 perovskite at high pressure and high temperature

Abstract

To obtain higher pressures in a Kawai-type apparatus, we explored and tested high-pressure cell assemblies suitable for experiments using sintered diamond (SD) anvils. As a result, we succeeded in generating pressures exceeding 55 GPa at temperatures of ~1000 °C in a Kawai-type apparatus (SPEED Mk-II) at SPring-8. Using the optimized cell assembly, we examined the stability field of MnGeO 3 perovskite, an analog of MgSiO 3 perovskite, which was recently found to transform to a new high-pressure form under the P-T conditions near the core-mantle boundary. From our in situ X-ray observations, MnGeO 3 perovskite was found to be stable at pressures up to 56–57 GPa at temperatures of 800–1050 °C.