Equation of State of Gallium Oxide to 70 Gpa: Comparison of Quasihydrostatic and Nonhydrostatic Compression

Authors

Kristina E. Lipinska-Kalita, University of Nevada, Las VegasFollow
Patricia Kalita, University of Nevada, Las VegasFollow
Oliver Hemmers, University of Nevada, Las VegasFollow
Thomas Hartmann, Harry Reid Center for Environmental StudiesFollow

Document Type

Article

Publication Date

3-2008

Publication Title

Physical Review B

Publisher

American Physical Society

Volume

77

Issue

9

First page number:

094123-1

Last page number:

094123-9

Abstract

Synchrotron x-ray diffraction and diamond-anvil cell techniques were used to characterize pressure induced structural modifications in gallium oxide. Gallium oxide was studied on compression up to 70 GPa and on the following decompression. The effect of the pressure-transmitting medium on the structural transformations was investigated in two sets of compression and decompression runs, one with nitrogen as a quasihydrostatic pressure-transmitting medium and the other in nonhydrostatic pressure conditions. The x-ray diffraction data showed gradual phase transition from a low-density, monoclinic β-Ga₂O₃ to a high-density, rhombohedral α-Ga₂O₃. With the use of nitrogen as a pressure transmitting medium, the β- to α-Ga₂O₃ transition begins at about 6.5–7 GPa and extends up to ∼40 GPa, confirming recent theoretical calculations. This pressure-driven transition is irreversible and the material decompressed from 70 GPa to ambient conditions was composed, in both sets of experimental runs, of α-Ga₂O₃ only. A Birch-Murnaghan fit of the unit cell volume as a function of pressure yielded a zero pressure bulk modulus K₀=199(6) GPa, and its pressure derivative K₀^′=3.1(4) for theβ-Ga₂O₃ phase, and K₀=220(9) GPa and K₀^′=5.9(6) for the α-Ga₂O₃ phase for the experiments performed in quasihydrostatic compression conditions. When for the same experiment K₀^′ is held at 4, then the bulk modulus values are 184(3) and 252(14) GPa for β-Ga₂O₃ and the α-Ga₂O₃, respectively. We compare the results of this work with our previous studies on the high-pressure behavior of nanocrystalline gallium oxide

Controlled Subject

Gallium compounds; High pressure crystallography; Nanocrystals

Disciplines

Biological and Chemical Physics | Chemistry | Inorganic Chemistry | Materials Chemistry | Physical Chemistry

Language

English

Permissions

Copyright American Physical Society. Used with permission.

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

Repository Citation

Lipinska-Kalita, K. E., Kalita, P., Hemmers, O., Hartmann, T. (2008). Equation of State of Gallium Oxide to 70 Gpa: Comparison of Quasihydrostatic and Nonhydrostatic Compression. Physical Review B, 77(9), 094123-1-094123-9.
https://digitalscholarship.unlv.edu/hrc_fac_articles/9