The P-V-T equation of state of CaPtO3 post-perovskite
The P-V-T equation of state of CaPtO3 post-perovskite
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CaPtO3后钙钛矿的P-V-T状态方程
DOI：
10.1007/s00269-012-0548-2
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发表时间：
2012
影响因子：
1.4
通讯作者：
Hunt S
中科院分区：
文献类型：
--
作者：
Hunt S
斜方晶后钙钛矿CaPtO 3与后钙钛矿MgSiO 3是同构的，后者是一种仅在100 GPa以上稳定的深土相。利用能量色散X射线衍射数据（9.4GPa和1, 024 K），结合已发表的等温和等压测量数据，确定了CaPtO_3的P-V-T状态方程（EoS）。使用三阶Birch-Murnaghan EoS，其中体积热膨胀系数（在大气压下）由α（T）= α0+ α1（T）表示。拟合参数的值为：等温不可压缩性，= 168.4（3）GPa;= 4.48（3）（均在298 K时）;= −0.032（3）GPa K−1; α0= 2.32（2）× 10− 5 K −1; α1= 5.7（4）× 10− 9 K −2。体积等温Anderson-Grüneisen参数δT在298 K时为7.6（7）。CaPtO 3与最近报道的CaIrO 3相似，与MgSiO 3后钙钛矿在高压下发现的值（−0.0085（11）至−0.024 GPa K−1）显著不同。我们还发现了类似形式的P-V-TEoS，这是任何后钙钛矿的第一个。拟合到轴的立方体上，得到= −0.038（4）GPa K−1;= −0.021（2）GPa K−1;= −0.026（5）GPa K−1，δT分别为8.9（9）、7.4（7）和4.6（9）。虽然b轴的不可压缩性最低，但它对温度的依赖性最小。
Orthorhombic post-perovskite CaPtO3is isostructural with post-perovskite MgSiO3, a deep-Earth phase stable only above 100 GPa. Energy-dispersive X-ray diffraction data (to 9.4 GPa and 1,024 K) for CaPtO3have been combined with published isothermal and isobaric measurements to determine itsP–V–Tequation of state (EoS). A third-order Birch–Murnaghan EoS was used, with the volumetric thermal expansion coefficient (at atmospheric pressure) represented byα(T) = α0+ α1(T). The fitted parameters had values: isothermal incompressibility,= 168.4(3) GPa;= 4.48(3) (both at 298 K);= −0.032(3) GPa K−1; α0= 2.32(2) × 10−5K−1; α1= 5.7(4) × 10−9K−2. The volumetric isothermal Anderson–Grüneisen parameter,δT, is 7.6(7) at 298 K.for CaPtO3is similar to that recently reported for CaIrO3, differing significantly from values found at high pressure for MgSiO3post-perovskite (−0.0085(11) to −0.024 GPa K−1). We also reportaxialP–V–TEoS of similar form, the first for any post-perovskite. Fitted to the cubes of the axes, these gave= −0.038(4) GPa K−1;= −0.021(2) GPa K−1;= −0.026(5) GPa K−1, withδT= 8.9(9), 7.4(7) and 4.6(9) fora,bandc,respectively. Althoughis lowest for theb-axis, its incompressibility is the least temperature dependent.