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Synthesis and Microdiffraction at Extreme Pressures and Temperatures
Published on: October 7, 2013
A new polymorph of FeAlO3 at high pressure
Takaya Nagai1, Daisuke Hamane, P Sujatha Devi
1Division of Earth and Planetary Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan. nagai@ep.sci.hokudai.ac.jp
The Journal of Physical Chemistry. B
|July 21, 2006
Summary
Researchers synthesized a new iron aluminum oxide (FeAlO3) polymorph under extreme pressure and temperature. This high-pressure phase transforms to a trigonal structure, suggesting a corundum-type crystal structure.
Area of Science:
- Materials Science
- Geophysics
- Solid State Chemistry
Background:
- Understanding the high-pressure behavior of iron aluminum oxide (FeAlO3) is crucial for geophysical and materials science applications.
- Previous studies have not fully characterized the high-pressure polymorphs of FeAlO3.
Purpose of the Study:
- To synthesize and characterize a new polymorph of FeAlO3 at high pressure and temperature.
- To determine the crystal structure of the synthesized FeAlO3 polymorph and its high-pressure phase.
Main Methods:
- Synchrotron X-ray diffraction was employed to analyze the structural changes of FeAlO3.
- High-pressure and high-temperature synthesis was performed at approximately 1800 K and 72 GPa.
Main Results:
- A new orthorhombic polymorph of FeAlO3 was successfully synthesized at 1800 K and 72 GPa.
- The orthorhombic phase transformed into a trigonal phase upon pressure release.
- Analysis of the trigonal phase's c/a ratio (approx. 2.71) suggests a corundum-type structure, distinct from LiNbO3 or ilmenite.
- The high-pressure orthorhombic phase is likely the Rh2O3(II) structure, not the GdFeO3-type perovskite.
Conclusions:
- The study identified a novel high-pressure polymorph of FeAlO3 with an orthorhombic structure.
- The findings indicate that FeAlO3 adopts a corundum-type structure at ambient pressure after high-pressure synthesis.
- This research contributes to understanding the phase diagram and structural behavior of FeAlO3 under extreme conditions.
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