Other
Scientific paper
Dec 2008
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008agufmmr31a1820b&link_type=abstract
American Geophysical Union, Fall Meeting 2008, abstract #MR31A-1820
Other
3924 High-Pressure Behavior, 3929 Nmr, Mossbauer Spectroscopy, And Other Magnetic Techniques, 3999 General Or Miscellaneous
Scientific paper
Fe2O3 post-perovskite is the high-pressure stable phase of Fe2O3 hematite (P > 60 GPa) and is the Fe end-member of (Mg,Fe)(Si,Fe)O3 post-perovskite. The stable spin arrangement and spin state of Fe2O3 post-perovskite are currently unknown. A better understanding of the high-pressure magnetic signature of Fe2O3 post-perovskite will help explain changes in the magnetic patterns on planetary bodies (e.g., the moon and Mars) due to shock events and could shed light on properties of the D" layer. We use ab initio calculations to calculate the stable magnetic arrangements and spin states at lower-mantle pressures. Antiferromagnetic arrangements are generally found to be more stable than ferromagnetic. At pressures below 70 GPa, we find the most stable magnetic arrangement has anti-parallel spins between the A- and B-sites (all Fe atoms on the A, bipolar prismatic site, are spin up, all Fe atoms on the B, octahedral sites, are spin down). However, at pressures above 70 GPa, the most stable arrangement has anti-parallel spins between the A-site iron atoms and between the B-site iron atoms. Although iron in both sites are high-spin below 70 GPa, the B-site iron atoms transform to low- spin, and the A-site iron atoms remain high-spin above 70 GPa. We also conducted Synchrotron Mössbauer spectroscopy of Fe2O3 post-perovskite at 70 GPa in the laser-heated diamond anvil cell at Sector 3 of Advanced Photon Source. The measured spectrum indicates spin ordering in Fe2O3 post-perovskite consistent with our calculations. Also the measured quadrupole splitting and magnetic hyperfine field suggest that at least half of iron is in the high-spin state, which are largely consistent with the calculations.
Bengtson Amelia
Morgan Daniel
Shim Sangwoo
No associations
LandOfFree
Stable Spin and Magnetic Arrangements in Fe2O3 Post-Perovskite does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Stable Spin and Magnetic Arrangements in Fe2O3 Post-Perovskite, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stable Spin and Magnetic Arrangements in Fe2O3 Post-Perovskite will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1242557