Abstract
In this decade, attainable pressure range in a Kawai-type high-pressure apparatus equipped with sintered diamond as second stage anvil is significantly increased and we generated pressure to 97.2 GPa measured by in situ X-ray observation at SPring-8. By using this technique, we measured compressibility of (Fe0.08Mg0.92)SiO3 perovskite up to more than 90 GPa. The bulk modulus and its pressure derivative are determined to be 268 GPa and 3.8, respectively. These values are slightly different from previous results. However, we obtained consistent results with previous study of bulk modulus of 257 GPa and pressure derivative of 4.3 when we fitted the data in the pressure range less than 70 GPa. The change of compressibility may indicate the spin transition in Fe-bearing perovskite around 70 GPa as suggested by previous study, for example, electrical conductivity measurement, X-ray emission method and so on.
