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Title: Low-energy planar magnetic defects in BaFe 2 As 2 : Nanotwins, twins, antiphase, and domain boundaries

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 assessed “ordered” moments from longer spatial and/or time averaging and should be considered directly.
 [1] ;  [2] ;  [3]
  1. Univ. of Illinois, Urbana-Champaign, IL (United States); Ames Lab., Ames, IA (United States)
  2. Ames Lab., Ames, IA (United States); Indian Inst. of Technology (IIT), Mumbai (India)
  3. Univ. of Illinois, Urbana-Champaign, IL (United States); Ames Lab., Ames, IA (United States); Iowa State Univ., Ames, IA (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
IS--J 8205
Journal ID: ISSN 1098-0121; PRBMDO
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter and Materials Physics; Journal Volume: 88; Journal Issue: 18
American Physical Society (APS)
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States