Raman spectroscopy of CaIrO[subscript 3] postperovskite up to 30 GPa

Journal Article · Mon Oct 20 04:00:00 EDT 2008 · Am. Mineral.

DOI:https://doi.org/10.2138/am.2008.2938· OSTI ID:1006899

Hustoft, J; Shim, S -H; Kubo, A; Nishiyama, N ^[1]

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1. MIT

We have measured Raman spectra of the postperovskite (PPv) phase in CaIrO{sub 3} up to 30 GPa to constrain the Grueneisen parameter ({gamma}). We identified a total of 4 strong modes between 200 and 650 cm{sup -1}, which is in contrast with the Raman spectra of Mn{sub 2}O{sub 3} and MgGeO{sub 3}-PPv where at least nine different modes have been detected. We found no sign of a phase transition in the Raman spectra of PPv CaIrO{sub 3}, which supports the stability of the PPv phase up to 30 GPa and room temperature in CaIrO{sub 3}. the spectroscopic Grueneisen parameter, {gamma}{sub sp,0} = 1.66--1.72, constrained from our Raman data, is in excellent agreement with the thermodynamic Grueneisen parameter, {gamma}{sub th,0} = 1.75 {+-} 0.05, calculated from recent XRD measurements (Martin et al. 2007) on CaIrO{sub 3}-PPv synthesized at high pressure and temperature similar to our starting material. Our result suggests that {gamma}{sub sp} constrained by Raman measurements provides a reasonable estimate on the {gamma}{sub th} of the PPv phase in CaIrO{sub 3}.

• Research Organization: Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
• Sponsoring Organization: USDOE
• OSTI ID: 1006899
• Journal Information: Am. Mineral., Journal Name: Am. Mineral. Journal Issue: (10) ; 10, 2008 Vol. 93; ISSN AMMIAY; ISSN 0003-004X
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

58 GEOSCIENCES
CALCIUM OXIDES
EQUATIONS OF STATE
GRUENEISEN CONSTANT
IRIDIUM OXIDES
PEROVSKITES
PHASE TRANSFORMATIONS
PRESSURE RANGE GIGA PA
RAMAN SPECTRA
RAMAN SPECTROSCOPY
STABILITY
TEMPERATURE DEPENDENCE
THERMODYNAMICS
X-RAY DIFFRACTION