Hybrid DFT calculation of 57Fe NMR resonances and orbital order in magnetite
Citation:
C. H. Patterson, Hybrid DFT calculation of 57Fe NMR resonances and orbital order in magnetite, Physical Review B, 90, 7, 2014, 075134 1-11Download Item:
PhysRevB.90.075134.pdf (PDF) 1.982Mb
Abstract:
The crystal structure and charge and orbital order of magnetite below the Verwey temperature are calculated
using a first-principles hybrid density functional theory (DFT) method. The initial atomic positions in the
crystal-structure calculation are those recently refined from x-ray diffraction data for the
Cc
space-group unit
cell [Senn, Wright, and Attfield,
Nature (London)
481
,
173
(
2012
)]. Fermi contact and magnetic dipolar
contributions to hyperfine fields at
57
Fe nuclei obtained from hybrid DFT calculations are used to obtain
NMR resonance frequencies for magnetite for a range of external magnetic field directions in a relatively
weak field. NMR frequencies from hybrid density functional theory calculations are compared to NMR
data [M. Mizoguchi,
J. Phys. Soc. Jpn.
70
,
2333
(
2001
)] for a range of applied magnetic field directions.
NMR resonance frequencies of
B
-site Fe ions show large relative variations with applied field direction
owing to anisotropic hyperfine fields from charge and orbital ordered Fe 3
d
minority-spin electrons at
those sites. Good agreement between computed and measured NMR resonance frequencies confirms the
pattern of charge and orbital order obtained from calculations. The charge and orbital order of magne-
titeinitslow-temperaturephaseobtainedfromhybridDFTcalculationsisanalyzedintermsofone-electronbonds
between Fe ions. The Verwey transition in magnetite therefore resembles Mott-Peierls transitions in vanadium
oxides which undergo symmetry-breaking transitions owing to electron-pair bond formation
Sponsor
Grant Number
Science Foundation Ireland (SFI)
09/RFP/MTR/2295
Author's Homepage:
http://people.tcd.ie/cpttrsonDescription:
PUBLISHEDSupplementary material available online at journal archive
Author: PATTERSON, CHARLES
Sponsor:
Science Foundation Ireland (SFI)Type of material:
Journal ArticleCollections:
Series/Report no:
Physical Review B90
7
Availability:
Full text availableSubject (TCD):
Nanoscience & Materials , Magnetism and spin electronicsThe following license files are associated with this item: