at Google ScholarTitle data
Satta, Niccolò ; Criniti, Giacomo ; Kurnosov, Alexander ; Boffa Ballaran, Tiziana ; Ishii, Takayuki ; Marquardt, Hauke:
Elastic anomalies across the P2₁nm→Pnnm structural phase transition in δ-(Al,Fe)OOH.
In: American Mineralogist.
Vol. 109
(2024)
Issue 11
.
- pp. 1934-1944.
ISSN 1945-3027
DOI: https://doi.org/10.2138/am-2023-9129
Abstract in another language
Hydrogen may be recycled into the Earth’s lower mantle by subduction and stabilized in solid solutions between phase H (MgSiO4H2), δ-AlOOH, ε-FeOOH, and SiO2 post-stishovite. In high-pressure oxyhydroxide phases, hydrogen is incorporated following the typical (OHO) sequence, adopting the asymmetric configuration O-H···O that evolves into a symmetric disordered state upon compression. Moreover, these iron-bearing aluminum oxyhydroxides δ-(Al,Fe)OOH present a structural phase transition from P21nm to Pnnm as pressure increases. Here, the single-crystal elasticity of the P21nm phase of δ-(Al0.97Fe0.03)OOH has been experimentally determined across the P21nm→Pnnm transition up to 7.94(2) GPa by simultaneous single-crystal X-ray diffraction (XRD) and Brillouin scattering at high pressures. The transition appears to be continuous, and it can be described with a second-, fourth-, and sixth-order terms Landau potential. Our results reveal an enhanced unit-cell volume compressibility, which is linked to an increase of the b- and a-axes linear compressibility in the P21nm phase of δ-(Al0.97Fe0.03)OOH prior to the transition. In addition, we observed the presence of elastic softening in the P21nm phase that mostly impacts the elastic stiffness coefficients c12, c22, and c23. The observed elastic anomalies cause a significant change in the pressure dependence of the adiabatic bulk modulus (KS). These results provide a better understanding of the relation between elasticity, P21nm→Pnnm structural phase transition, and hydrogen dynamics in δ-(Al0.97Fe0.03)OOH, which may be applied to other O-H···O-bearing phases.
Further data
| Item Type: | Article in a journal |
|---|---|
| Refereed: | Yes |
| Institutions of the University: | Research Institutions > Central research institutes > Bavarian Research Institute of Experimental Geochemistry and Geophysics - BGI |
| Result of work at the UBT: | Yes |
| DDC Subjects: | 500 Science > 550 Earth sciences, geology |
| Date Deposited: | 02 Jun 2025 12:49 |
| Last Modified: | 02 Jun 2025 12:49 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/93830 |