Document Detail

Pressure-induced crystal structure and spin-state transitions in magnetite (Fe3O4).
MedLine Citation:
PMID:  22823905     Owner:  NLM     Status:  Publisher    
High pressure is an important dimension for the emergent phenomena in transition metal oxides, including high-temperature superconductivity, colossal magnetoresistance, and magnetoelectric coupling. In these multiply correlated systems, the interplay between lattice, charge, orbital, and spin is extremely susceptible to external pressure. Magnetite (Fe3O4), as one of oldest known magnetic materials and magnetic minerals, its high pressure behaviors, however, are still not clear. In particular, the crystal structure of high pressure phase has remained contentious. Here, we investigate the pressure-induced phase transitions in Fe$_3$O$_4$ from first-principles density-functional theory. It is revealed that the net magnetic moment, arising from two ferrimagnetic coupled sublattices in Fe$_3$O$_4$, shows an abrupt drop when entering into high pressure phase, but recovers finite value when the pressure is beyond 65.1 GPa. The origin lies in the redistribution of Fe $3d$ orbital occupation with the change of crystal field, where successive structural transitions from ambient pressure phase $Fd\bar{3}m$ to high pressure phase $Pbcm$ (at 29.7 GPa), and further to $Bbmm$ (at 65.1 GPa), are established accurately. These findings not only explain the experimental observations on the structural and magnetic properties of the highly compressed Fe$_3$O$_4$, but also suggest the existence of highly magnetized magnetite in the Earth's lower mantle.
Sheng Ju; Tian-Yi Cai; Hai-Shuang Lu; Chang-De Gong
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-7-23
Journal Detail:
Title:  Journal of the American Chemical Society     Volume:  -     ISSN:  1520-5126     ISO Abbreviation:  -     Publication Date:  2012 Jul 
Date Detail:
Created Date:  2012-7-24     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7503056     Medline TA:  J Am Chem Soc     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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