Iron oxides are among the major constituents of the deep Earth’s interior. Among them, the epsilon phase of Fe2O3 is one of the less studied polymorphs and there is a lack of information about its structural, electronic and magnetic transformations at extreme conditions. Here we report the precise determination of its equation of state and a deep analysis of the evolution of the polyhedral units under compression, thanks to the agreement between our experiments and ab-initio simulations. Our results indicate that this material, with remarkable magnetic properties, is stable at pressures up to 27 GPa. Above 27 GPa, a volume collapse has been observed and ascribed to a change of the local environment of the tetrahedrally coordinated iron towards an octahedral coordination, finding evidence for a different iron oxide polymorph.

Sans, J., Monteseguro, V., Garbarino, G., Gich, M., Cerantola, V., Cuartero, V., et al. (2018). Stability and nature of the volume collapse of epsilon-Fe2O3 under extreme conditions. NATURE COMMUNICATIONS, 9(1) [10.1038/s41467-018-06966-9].

Stability and nature of the volume collapse of epsilon-Fe2O3 under extreme conditions

Cerantola V;
2018

Abstract

Iron oxides are among the major constituents of the deep Earth’s interior. Among them, the epsilon phase of Fe2O3 is one of the less studied polymorphs and there is a lack of information about its structural, electronic and magnetic transformations at extreme conditions. Here we report the precise determination of its equation of state and a deep analysis of the evolution of the polyhedral units under compression, thanks to the agreement between our experiments and ab-initio simulations. Our results indicate that this material, with remarkable magnetic properties, is stable at pressures up to 27 GPa. Above 27 GPa, a volume collapse has been observed and ascribed to a change of the local environment of the tetrahedrally coordinated iron towards an octahedral coordination, finding evidence for a different iron oxide polymorph.
Articolo in rivista - Articolo scientifico
e-Fe2O3; synchrotron; Mössbauer spectroscopy; XRD; EXAFS; high pressure; diamond anvil cell
English
Sans, J., Monteseguro, V., Garbarino, G., Gich, M., Cerantola, V., Cuartero, V., et al. (2018). Stability and nature of the volume collapse of epsilon-Fe2O3 under extreme conditions. NATURE COMMUNICATIONS, 9(1) [10.1038/s41467-018-06966-9].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/397742
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