Thermal Equation of State of CaGeO3 Perovskite
Pressure-volume-temperature data have been obtained for CaGeO3 perovskite up to 9.6 GPa and 1100 K using a cubic anvil, DIA-type high-pressure apparatus in conjunction with synchrotron X-ray diffraction. The data were analyzed using Birch-Murnaghan equation of state and thermal pressure approach with the bulk modulus at ambient pressure, KT0, and its pressure derivative, K'T0, constrained by previous measurements. A fit of the unit-cell volume data to the high-temperature Birch-Murnaghan (HTBM) equation of state gives ({sub partial}KT/{sub partial}T)P = -0.025 {+-} 0.015 GPa/K, a = 1.047 {+-} 0.356 x 10-5/K, and b = 3.282 {+-} 0.735 x 10-8/K2 for the thermal expansion {alpha} expressed by a + bT. The thermal pressure approach yields {alpha}KT = 4.04 {+-} 0.37 x 10-3 GPa/K and ({sub partial}2P/{sub partial}T2)V = 6.17 {+-} 1.28 x 10-6 GPa/K2. The energy dispersive X-ray diffraction data reveal no indication of a structural phase transition over the P-T range of the current experiment. A systematic relationship, KS0 = 6720/V(molar) - 13.07 GPa, has been established based on these isostructural analogues, which predicts KS0 = 261(15) for MgSiO3 perovskite and 225(8) for CaSiO3 perovskite, respectively.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
- Sponsoring Organization:
- Doe - Office Of Science
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 959617
- Report Number(s):
- BNL-82603-2009-JA; AMMIAY; TRN: US1005762
- Journal Information:
- American Mineralogist, Vol. 93; ISSN 0003-004X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Elasticity of Polycrystalline Pyrope (Mg3Al2Si3O12) to 9 GPa and 1000°C
Thermal Equation of State of (Mg0.9Fe0.1)2SiO4 Olivine