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

Sans, J. A.; Monteseguro, V.; Garbarino, G.; Gich, M.; Cerantola, V.; Cuartero, V.; Monte, M.; Irifune, T.; Munoz, A.; Popescu, C.

NATURE COMMUNICATIONS
2018
VL / 9 - BP / - EP /
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.

AccesS level

Green published, Gold

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