Research ArticleQUANTUM PHYSICS

Direct observation of Σ7 domain boundary core structure in magnetic skyrmion lattice

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Science Advances  12 Feb 2016:
Vol. 2, no. 2, e1501280
DOI: 10.1126/sciadv.1501280
  • Fig. 1 TEM/STEM characterization of a thin film of FeGe1−xSix.

    (A) Low-magnification TEM bright-field image of the thin film. Only three grains are labeled as I, II, and III. The arrows indicate the grain boundary between grain I and grain II. (B) Higher-magnification image of the area designated by a white rectangle in (A). (C) Selected-area electron diffraction pattern obtained from grain I. (D) HAADF STEM image obtained from grain I. (E) Atomic model viewed along the [211] zone axis.

  • Fig. 2 Magnetic stripes emerging under zero field–cooled conditions at 95 K.

    (A) Magnetic helicity image showing clear stripe contrast in the vicinity of grain boundaries. (Inset) An enlarged image near the triple junction of the three grains indicated by a blue rectangle. Arrows indicate magnetic dislocation–like structures. (B) Circular stripes that emerged after the application of an intense perpendicular magnetic field. (C and D) Reconstructed in-plane magnetization vector maps obtained by DPC STEM in two different areas near the grain boundary between grain I and grain II.

  • Fig. 3 Skyrmion hexagonal lattice in the vicinity of grain boundaries.

    (A) Reconstructed in-plane magnetization vector map of a hexagonal skyrmion lattice. (B) Corresponding magnetic helicity and (C) annular dark field image. (D) Enlarged view of the skyrmion lattice shown in (A).

  • Fig. 4 Core structure of the skyrmion Σ7 domain boundary.

    (A) Large field-of-view magnetic helicity image. Two helicity images are merged to show the whole domain boundary structure (see fig. S3 for original images). (B) Enlarged magnetic helicity image of the region indicated by a blue rectangle in (A) showing the core structure of the skyrmion Σ7 domain boundary. (C) DPC reconstructed in-plane magnetization map of the skyrmion domain boundary shown in (B). (D) Extracted images of individual skyrmions in the domain boundary core region. The elongated (E1-E3), shrunk (S1-S3), and regular (R1-R3) images of skyrmions can be found.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/2/2/e1501280/DC1

    Note S1. Brief description of the DPC STEM system.

    Fig. S1. Schematic of DPC STEM.

    Fig. S2. Reconstruction processes in DPC STEM.

    Fig. S3. Selected-area electron diffraction patterns from 10 numbered areas.

    Fig. S4. HAADF STEM image of the area near the structural grain boundary between grain I and grain II, where we performed STEM EDX characterization.

    Fig. S5. Process to synthesize Fig. 4A.

    Fig. S6. Preliminary quantitative analysis of the flexibility of skyrmions.

    Fig. S7. Another example of magnetic Σ7 domain boundary.

    Table S1. Specimen tilting angles for the selected-area electron diffraction patterns listed in fig. S3.

    Table S2. STEM EDX characterization of the thin film.

  • Supplementary Materials

    This PDF file includes:

    • Note S1. Brief description of the DPC STEM system.
    • Fig. S1. Schematic of DPC STEM.
    • Fig. S2. Reconstruction processes in DPC STEM.
    • Fig. S3. Selected-area electron diffraction patterns from 10 numbered areas.
    • Fig. S4. HAADF STEM image of the area near the structural grain boundary between grain I and grain II, where we performed STEM EDX characterization.
    • Fig. S5. Process to synthesize Fig. 4A.
    • Fig. S6. Preliminary quantitative analysis of the flexibility of skyrmions.
    • Fig. S7. Another example of magnetic Σ7 domain boundary.
    • Table S1. Specimen tilting angles for the selected-area electron diffraction patterns listed in fig. S3.
    • Table S2. STEM EDX characterization of the thin film.

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