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Giant positive magnetoresistance in half-metallic double-perovskite Sr2CrWO6 thin films

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Science Advances  03 Nov 2017:
Vol. 3, no. 11, e1701473
DOI: 10.1126/sciadv.1701473
  • Fig. 1 The AFM and TEM morphologies of the SCWO films.

    (A) S-1 (12 nm thick). (B) S-2 (24 nm thick). (C) S-3 (48 nm thick). The surface roughness increases with film thickness with values of 348.4 pm, 502.7 pm, and 1.42 nm, respectively. (D) Cross-sectional TEM morphology of the S-3 films. (E and F) The homogeneous thin films, sharp substrate-film interface, and high-resolution TEM indicate the high quality of the films.

  • Fig. 2 Magnetization-magnetic field (M-H) curves of the S-1, S-2 and S-3 SCWO films.

    All films show well-saturated M-H loops, indicating the ferromagnetic nature.

  • Fig. 3 Temperature-dependent resistivity (ρ-T) and temperature-dependent MR of the SCWO films.

    ρ-T of (A) S-1, (B) S-2, and (C) S-3 without and with a magnetic field of 2 T. Without magnetic field, all films show metallic behavior indicated by the decreasing resistivity with decreasing field in the whole temperature range. When an applied magnetic field perpendicular to the thin film is applied, the resistivity tends to increase with decreasing field at the low temperature range. (D) MR-T of all the films. At 2 K with a magnetic field of 2 T, the positive MRs are 1960, 245, and 190% for the films, respectively.

  • Fig. 4 Temperature-dependent carrier density and mobility of the SCWO films.

    The films show very high carrier density and high mobility at low temperature; the inset depicts Hall coefficient.

  • Fig. 5 Theoretical calculated electronic properties of SCWO.

    (A) The spin-polarized band structure and (B) DOS of SCWO. Fermi energy is set to 0. The SCWO is a perfect half-metal with the total net spin moment is 2.0 μB/f.u.

  • Fig. 6 Magnetic field–dependent positive MR at 2, 4, 10, and 20 K for the SCWO films.

    (A) S-1. (B) S-2. (C) S-3. Giant positive MR with values of 17,200, 2060, and 1185%, respectively, can be observed at 2 K with a magnetic field of 7 T.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/11/e1701473/DC1

    fig. S1. XRD patterns of the SCWO films with different thicknesses.

    fig. S2. Field cooling (200 Oe) temperature-dependent magnetization of the S-1, S-2, and S-3 films.

    fig. S3. The methods for transport property measurement and the transport properties of the heated bare STO substrate and S-2 films with and without a magnetic field.

    fig. S4. XRD patterns of the SCWO films fabricated with oxygen pressures of 0.5 and 1.5 Pa.

    fig. S5. AFM and cross-sectional TEM images of the SCWO films fabricated with an oxygen pressure of 0.5 Pa.

    fig. S6. The temperature-dependent resistance of the films deposited under an oxygen pressure of 0.5 Pa.

    fig. S7. The temperature-dependent resistivity of the S-2 films with the external magnetic field parallel to the thin film but still perpendicular to the current.

    fig. S8. Field-dependent MR of the S-2 films up to 14 T.

    fig. S9. Evolution of magnetic structure and magnetic domain of the SCWO without and with a magnetic field.

    fig. S10. The valence states of Cr and W cations.

  • Supplementary Materials

    This PDF file includes:

    • fig. S1. XRD patterns of the SCWO films with different thicknesses.
    • fig. S2. Field cooling (200 Oe) temperature-dependent magnetization of the S-1, S-2, and S-3 films.
    • fig. S3. The methods for transport property measurement and the transport properties of the heated bare STO substrate and S-2 films with and without a magnetic field.
    • fig. S4. XRD patterns of the SCWO films fabricated with oxygen pressures of 0.5 and 1.5 Pa.
    • fig. S5. AFM and cross-sectional TEM images of the SCWO films fabricated with an oxygen pressure of 0.5 Pa.
    • fig. S6. The temperature-dependent resistance of the films deposited under an oxygen pressure of 0.5 Pa.
    • fig. S7. The temperature-dependent resistivity of the S-2 films with the external magnetic field parallel to the thin film but still perpendicular to the current.
    • fig. S8. Field-dependent MR of the S-2 films up to 14 T.
    • fig. S9. Evolution of magnetic structure and magnetic domain of the SCWO without and with a magnetic field.
    • fig. S10. The valence states of Cr and W cations.

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