title: Pressure-induced magnetization in FeO: evidence from elasticity and Mössbauer spectroscopy.
abstract: The complete elastic tensor of Fe0.94O (wüstite) has been determined to 10 GPa using acoustic interferometry at GHz frequencies inside a diamond-anvil cell. The soft mode (C44) elastic constant of FeO is reduced by 20% over the experimental pressure range. An unusual discontinuity in the pressure derivatives of C11 and C12 at 4.7+/-0.2 GPa corresponds to the pressure at which the onset of a magnetic ordering transition is observed by high-pressure Mössbauer spectroscopy and neutron powder diffraction. Our new results combined with literature structural high P-T data suggest that there is a magnetic, although still cubic, phase of FeO between approximately 5 and approximately 17 GPa.
authors.affiliation: Bayerisches Geoinstitut, D-95440 Bayreuth, Germany.
authors.forename: Anastasia P
authors.initials: AP
authors.lastname: Kantor
authors.forename: Steven D
authors.initials: SD
authors.lastname: Jacobsen
authors.forename: Innokenty Yu
authors.initials: IY
authors.lastname: Kantor
authors.forename: Leonid S
authors.initials: LS
authors.lastname: Dubrovinsky
authors.forename: Catherine A
authors.initials: CA
authors.lastname: McCammon
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Reichmann
authors.forename: Igor N
authors.initials: IN
authors.lastname: Goncharenko