Low-energy planar magnetic defects in BaFe2As2: Nanotwins, twins, antiphase, and domain boundaries

Journal Article · Tue Jan 01 04:00:00 EST 2013 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.88.184515· OSTI ID:1116491

Khan, S. N. ^[1]; Alam, A. ^[1]; Johnson, Duane D. ^[2]

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1. Ames Laboratory
2. University of Illinois, Urbana-Champaign

In BaFe2As2, structural and magnetic planar defects begin to proliferate below the structural phase transition, affecting descriptions of magnetism and superconductivity.We study, using density-functional theory, the stability and magnetic properties of competing antiphase and domain boundaries, twins and isolated nanotwins (twin nuclei), and spin excitations proposed and/or observed. These nanoscale defects have a very low surface energy (22 210 m Jm 2), with twins favorable to the mesoscale. Defects exhibit smaller moments confined near their boundaries making a uniform-moment picture inappropriate for long-range magnetic order in real samples. Nanotwins explain features in measured pair distribution functions so should be considered when analyzing scattering data. All these defects can be weakly mobile and/or can have fluctuations that lower

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1116491
• Journal Information: Physical Review B, Journal Name: Physical Review B Journal Issue: 18 Vol. 88; ISSN 1098-0121
• Country of Publication: United States
• Language: English