[S-IT19] 地球深部科学

[SIT19-P01] Single crystal elasticity and equation of state of tantalum up to 55 GPa

*米田 明¹、福井 宏之²、鎌田 誠司³、内山　 裕士²、平尾 直久²、Baron Alfred² (1.大阪大学理学研究科宇宙地球専攻、2.高輝度光科学研究センター、3.東北大学学際科学フロンティア研究所)

キーワード：タンタル、非弾性Ｘ線散乱、ダイヤモンドアンビルセル、結晶弾性、一次圧力スケール、ルビースケール

We measured single crystal elasticity of Ta under high pressure up to ~50 GPa at room temperature using inelastic x-ray scattering at room temperature. Simultaneously we measured the density of Ta using x-ray diffraction. Combining the bulk modulus and density, we obtain an equation of state of Ta as a primary scale. The Vinet equation was fitted to the pressure-volume data and we found consistency with previous work including experimental static and shock compressions and theoretical calculation. We proposed a parameter set for the Vinet equation (K₀=191.1(3) GPa, K’₀=4.006(2)) which is consistent with the primary pressure within 2% up to ~80 GPa. Furthermore, we found the present scale to be consistent with a recent ruby scale (Ruby2020) up to ~50 GPa.