Local structure and electronic-spin transition of Fe-bearing MgSiO3 perovskite under conditions of the Earth's lower mantle
2008 (English)In: Physics of the Earth and Planetary Interiors, ISSN 0031-9201, E-ISSN 1872-7395, Vol. 166, no 1-2, 77-82 p.Article in journal (Refereed) Published
We report first-principles electronic structure calculations on the structural and electronic-spin behaviours of Fe-bearing MgSiO3 crystals up to the pressure of Earth's mantle. The transition pressure of the Fe-bearing MgSiO3 from the orthorhombic perovskite (OPv) to the orthorhombic post-perovskite (OPPv) phase decreases with increasing Fe concentration. The lattice distortion has impacts on the electronic-spin behaviour of the Fe ions in the PVs. The spin-polarizations of the Fe ions in the (Fe,Mg)SiO3 OPvs and OPPvs keep unchanged up to the pressures in the lower mantle. Meanwhile, the Fe-bearing MgSiO3 OPV Containing Fe-Mg-Fe-Si pairs exhibits multiple-magnetic moments co-existing in a large pressure range (from about 78 to 110 GPa), and finally becomes non-magnetic at pressure higher than 110 GPa. These results provide a mechanism to understand the recent experimental results about Fe valence states and the electronic transitions of the Fe-bearing MgSiO3 under high pressure.
Place, publisher, year, edition, pages
2008. Vol. 166, no 1-2, 77-82 p.
iron-bearing, MgSiO3-perovskite and post-perovskite, Ab initio method, phase transition, electronic and spin transitions
IdentifiersURN: urn:nbn:se:uu:diva-112399DOI: 10.1016/j.pepi.2007.11.004ISI: 000253617500007OAI: oai:DiVA.org:uu-112399DiVA: diva2:286157