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Title:
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Itinerant magnetic excitations in antiferromagnetic CaFe2As2 |
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Author:
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Diallo, S.O.; Antropov, V.P.; Perring, T.G.; Broholm, C.; Pulikkotil, J.J.; Ni, N.; Bud'ko, S.L.; Canfield, P.C.; Kreyssig, A.; Goldman, A.I.; McQueeney, R.J. |
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Abstract:
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Neutron scattering measurements of the magnetic excitations in single crystals of antiferromagnetic CaFe2As2 reveal steeply dispersive and well-defined spin waves up to an energy of ~100 meV. Magnetic excitations above 100 meV and up to the maximum energy of 200 meV are however broader in energy and momentum than the experimental resolution. While the low energy modes can be fit to a Heisenberg model, the total spectrum cannot be described as arising from excitations of a local moment system. Ab initio calculations of the dynamic magnetic susceptibility suggest that the high energy behavior is dominated by the damping of spin waves by particle-hole excitations. |
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URI:
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http://jhir.library.jhu.edu/handle/1774.2/33734
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Date:
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2009-05-08 |
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Citation:
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Physical Review Letters 8 May 2009, vol.102, no.18, 187206 (4 pp
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Subject:
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neutron diffraction
magnetic susceptibility
magnetic moments
iron compounds
itinerant magnetic excitations;
neutron scattering
single crystals
spin waves
Heisenberg model
local moment system
calcium compounds
band model of magnetism
antiferromagnetic materials
ab initio calculations
dynamic magnetic susceptibility
particle-hole excitations
CaFe2As2
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