Influence of the Verwey Transition on the Spin-Wave Dispersion of Magnetite

Journal Article · Sat Jan 01 04:00:00 EST 2005 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.1846555· OSTI ID:1003094

McQueeny, R. J. ^[1]; Yethiraj, Mohana ^[2]; Montfrooij, W. ^[3]; Garner, J. S. ^[4]; Metcalf, P. ^[5]; Honig, J. M. ^[6]

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1. Ames Laboratory
2. ORNL
3. University of Missouri, Columbia
4. Brookhaven National Laboratory (BNL)
5. Purdue University
6. University of Purdue

Inelastic neutron-scattering measurements of the spin-wave spectrum of magnetite (Fe{sub 3}O{sub 4}) that shed new light on the Verwey transition problem are presented. Above the Verwey transition, the spin waves can fit a simple Heisenberg model. Below TV, a large gap (8?meV) forms in the acoustic spin-wave branch at q = (0,0,1/2) and E = 43?meV. Heisenberg models with large unit cells were used to examine the spin waves when the superexchange is modified to reflect the crystallographic symmetry lowering due to either atomic distortions or charge ordering and find that neither of these models predicts the spin-wave gap.

• Research Organization: Oak Ridge National Laboratory (ORNL); High Flux Isotope Reactor
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1003094
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 0 Vol. 97; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ACOUSTICS
CHARGES
DISPERSIONS
EXCHANGE INTERACTIONS
FERRIMAGNETISM
HEISENBERG MODEL
INELASTIC SCATTERING
IRON COMPOUNDS
MAGNETIC MOMENTS
MAGNETITE
NEUTRON DIFFRACTION
SPIN WAVES
SYMMETRY
UNITS
VISIBLE RADIATION