NAGAI Takaya Graduate School of Science, Osaka Univ. Research Associate, 大学院・理学研究科, 助手 (20243131)
OHTAKA Osamu Graduate School of Science, Osaka Univ. Associate Professor, 大学院・理学研究科, 助教授 (40213769)
YOSHIASA Akira Graduate School of Science, Osaka Univ. Associate Professor, 大学院・理学研究科, 助教授 (00191536)
SHIMOMURA Osamu Graduate School of Science, Osaka Univ., 放射光, 部長
YAGI Takehiko University of Tokyo Professor, 物性研究所, 教授 (20126189)
In order to understand dynamics of mantle or earth's shell, such as subduction of slab, mechanism of deep earthquake and mantle convection, in situ investigations of material sciences of constituent substances under high pressure and temperature are significant subject. Present experimental proposal is the collaboration works between French and Japanese geophysicists with mutual relations. By making use of the facilities in ESRF in Francc and SPring-8 and Photon Factory, phase transitions of oxides and silicates was studied under compression or stress field. Studies of solid state physics of electric conductivity, conductivity, elastic coefficient and thermal expansion coefficient were made using diamond anvil or multianvil high-pressure apparatus. The following experiments were executed :
Electric conductivity measurement of olivine (Mg1-x, Fex)2SiO4 under high pressure and high temperature was carried out by using multianvil high-pressure apparatus. Thc measurement was conducted at te
mperature up to 1000 and pressure up to 6GPa. Geothermal change with depth can be estimated from the experimental results
The electric conductivity measurement of Fe2SiO4 indicate a large gap of the conductivity at the olivine-spinel transition at about 6GPa. It is clarified that the carrier of the conduction is attributed to the Fe^<2+>⇔Fe^<3+> electron hopping rather than hole.
ÅiCRÅjBy using diamond anvil high-pressure cell, electric conductivity of wustite (Mg1-x, Fex)O, one of major lower mantle substance, was measured measurement as functions of pressure and temperature together with Fe composition (x=0.1, 0.3, 0.5). This experiment was carried out at Inst. Physque du Globe, ) Paris University. Activation energy of electric conductivity was elucidated. With increasing Fe content in the solid solution the conductivity is elevated. The d-electron configuration of Fe ion in the bonding electron raises the conductivity.
ÅiCSÅjCollaboration work with Prof.J.P.Poirier (Inst.Physque du Globe) is the investigation of the melting curve of iron metal, earth core material at extremely high temperature over 2000℃ under high pressure.The experiment was made with the multianvil apparatus and synchrotron radiation at SPring-8. For this experiment The present Grant-in-Aid supported the travel fee of Dr.Andrault. Dr.Ohtaka of Osaka University and Dr.Shimomura of SPring-8 stuff were supporting members.
All experimental results have been reported at several International Conference or workshop and they were published in the science journals. Less