Research ArticleCONDENSED MATTER PHYSICS

Magnetization switching using topological surface states

See allHide authors and affiliations

Science Advances  30 Aug 2019:
Vol. 5, no. 8, eaaw3415
DOI: 10.1126/sciadv.aaw3415
  • Fig. 1 Structural and electrical properties of Bi2Se3/BaFe12O19.

    (A) XRD spectrum of a 5-nm-thick BaFe12O19 film. a.u., arbitrary unit. (B) RHEED image of the Bi2Se3 film in a Bi2Se3 (6 nm)/BaFe12O19 (5 nm) sample. (C) Optical image of a Bi2Se3/BaFe12O19 Hall bar structure. (D) RH of the Bi2Se3 film as a function of magnetic field at different temperatures (T), as indicated. (E) Sheet carrier density as a function of T was calculated using the RH data in (D). The inset in (E) shows the EF estimated from the carrier density data. (F) Conductivity of the Bi2Se3 film as a function of T. The inset in (F) shows the same data but in a natural logarithm scale. The data in (D) and (F) were measured using the Hall bar device shown in (C).

  • Fig. 2 Magnetic properties and AHE resistance of Bi2Se3/BaFe12O19.

    (A) Magnetization (M) vs. field (H) loops measured with the same Bi2Se3/BaFe12O19 sample as the one whose RHEED image is shown in Fig. 1B. (B) Saturation magnetization (Ms) and coercive field (Hc) as a function of T measured with the same BaFe12O19 film as the one whose XRD spectrum is shown in Fig. 1A. (C and D) RAHE vs. field (H) loops measured at T = 300 K and T = 3 K, as indicated, using the Hall bar structure shown in Fig. 1C.

  • Fig. 3 SOT-induced switching in Bi2Se3/BaFe12O19.

    (A) Experimental configuration. (B to E) AHE resistance (RAHE) measured as a function of charge current (Idc) at different fields (H) and temperatures (T), as indicated. The arrows in (B) to (E) indicate the current sweeping directions.

  • Fig. 4 Effects of SOT on field switching in Bi2Se3/BaFe12O19 and Pt/BaFe12O19.

    (A) Effects of Idc on RAHE hysteresis loops at T = 3 K in Bi2Se3/BaFe12O19. (B) Switching field (Hsw) as a function of T measured at different Idc, as indicated, in Bi2Se3/BaFe12O19. (C) Hsw as a function of T measured at different Idc, as indicated, in Pt/BaFe12O19. (D) SOT efficiency (η) as a function of T in Bi2Se3/BaFe12O19 and Pt/BaFe12O19. The data were all measured at a field applied at an angle of 45° away from the film normal direction. The data on Pt/BaFe12O19 were measured with a Hall bar structure that had the same dimension as the Bi2Se3/BaFe12O19 Hall bar.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/8/eaaw3415/DC1

    Section S1. Anti-weak localization

    Section S2. T dependence of SOT

    Section S3. Micromagnetic simulations of SOT-induced magnetization switching

    Section S4. Estimation of SOT strength

    Section S5. Estimation of fermi level and carrier density

    Section S6. Cross-section image of Bi2Se3/BaFe12O19

    Fig. S1. Dependence of the conductivity of the Bi2Se3 film on a magnetic field applied along the film normal direction.

    Fig. S2. Simulated results on SOT-induced switching at T = 0 K and T = 300 K.

    Fig. S3. Simulated results on SOT-assisted field switching under the configuration are the same as that for Fig. 4 in the main text.

    Fig. S4. Estimation of strength of SOC and SOT in Bi2Se3/BaFe12O19.

    Fig. S5. Calculated EF and carrier densities.

    Fig. S6. High-resolution transmission electron microscopy image of the Bi2Se3/BaFe12O19 stack with Te capping layer.

    References (39, 40)

  • Supplementary Materials

    This PDF file includes:

    • Section S1. Anti-weak localization
    • Section S2. T dependence of SOT
    • Section S3. Micromagnetic simulations of SOT-induced magnetization switching
    • Section S4. Estimation of SOT strength
    • Section S5. Estimation of fermi level and carrier density
    • Section S6. Cross-section image of Bi2Se3/BaFe12O19
    • Fig. S1. Dependence of the conductivity of the Bi2Se3 film on a magnetic field applied along the film normal direction.
    • Fig. S2. Simulated results on SOT-induced switching at T = 0 K and T = 300 K.
    • Fig. S3. Simulated results on SOT-assisted field switching under the configuration are the same as that for Fig. 4 in the main text.
    • Fig. S4. Estimation of strength of SOC and SOT in Bi2Se3/BaFe12O19.
    • Fig. S5. Calculated EF and carrier densities.
    • Fig. S6. High-resolution transmission electron microscopy image of the Bi2Se3/BaFe12O19 stack with Te capping layer.
    • References (39, 40)

    Download PDF

    Files in this Data Supplement:

Navigate This Article