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Phase transitions and iron-ordered moment form factor in LaFeAsO
Physical Review B
  • H.-F. Li, Iowa State University
  • W. Tian, Iowa State University
  • J.-Q. Yan, Iowa State University
  • Jerel L. Zarestky, Iowa State University
  • R. William McCallum, Iowa State University
  • Thomas A. Lograsso, Iowa State University
  • David Vaknin, Iowa State University
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Elastic neutron-scattering studies of single-crystal LaFeAsO reveal that upon cooling, an onset of the tetragonal (T)-to-orthorhombic (O) structural transition occurs at TS≈156 K, and it exhibits a sharp transition at TP≈148 K. We argue that in the temperature range TS to TP, T and O structures may dynamically coexist possibly due to nematic spin correlations recently proposed for the iron pnictides, and we attribute TP to the formation of long-range O domains from the finite local precursors. The antiferromagnetic structure emerges at TN≈140 K, with the iron moment direction along the O a axis. We extract the iron magnetic form factor and use the tabulated ⟨j0⟩ of Fe, Fe2+, and Fe3+ to obtain a magnetic moment size of ∼0.8 μB at 9.5 K.

This article is from Physical Review B 82 (2010): 064409, doi:10.1103/PhysRevB.82.064409.

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American Physical Society
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H.-F. Li, W. Tian, J.-Q. Yan, Jerel L. Zarestky, et al.. "Phase transitions and iron-ordered moment form factor in LaFeAsO" Physical Review B Vol. 82 Iss. 6 (2010) p. 064409
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