[S-MP44] [JJ] 鉱物の物理化学

[SMP44-01] 高圧下での金の結晶弾性測定：~5GPa領域弾性異常と一次圧力スケールの構築

*米田 明¹、福井 宏之²、五味 斎¹、鎌田 誠司⁴、Xie Longjian¹、平尾 直久⁵、内山 裕士⁵、筒井 智嗣⁵、バロン アルフレッド³ (1.岡山大学惑星物質研究所、2.兵庫県立大物質理学研究科、3.理化学研究所、4.東北大学理学研究科、5.高輝度光科学研究センター)

キーワード：金、結晶弾性、体積弾性率、圧力スケール、非弾性X線散乱、ダイヤモンド・アンビル・セル

We measured single crystal elasticity of gold (Au) as well as its lattice parameters simultaneously under high pressure by using inelastic X ray scattering (IXS) technique. Generated pressure and elastic moduli of gold were obtained only from the present experimental data at five pressure points between 0 and 20 GPa by direct numerical integration. Pressure variation of the bulk modulus displays an anomalous behavior; it is nearly constant up to ~5 GPa, and then steeply increases toward higher pressure. Similar anomaly is observed in independent first-principles calculations as well. The absolute pressure scale determined from the present results gives systematically lower pressures than those from the previous pressure scales owing to the bulk modulus anomaly founded in this study.