Research ArticleCONDENSED MATTER PHYSICS

Antisymmetric magnetoresistance in van der Waals Fe3GeTe2/graphite/Fe3GeTe2 trilayer heterostructures

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Science Advances  05 Jul 2019:
Vol. 5, no. 7, eaaw0409
DOI: 10.1126/sciadv.aaw0409
  • Fig. 1 Overview of the MR effect in FGT/graphite/FGT heterostructures.

    (A) Optical and AFM images of an FGT/graphite/FGT heterostructure. The device number is FPC3. Scale bars, 5 μm. The regions surrounded by the blue line, red line, and yellow line represent the top FGT layer, graphite layer, and bottom FGT layer, respectively. (B) Schematic diagram for the transport behavior of a typical GMR effect. (C) Field-dependent Rxx and Rxy measurements of an FGT/graphite/FGT heterostructure (sample FPC3) at 50 K. A loop surrounded by a dark blue dashed line is shown in the Rxx(B) curve. (D) ΔRxx/Rxx values for samples with various thicknesses of graphite layer. All the data are calculated for measurements at 50 K. The error bars come from the noise of the measurement.

  • Fig. 2 Temperature-dependent transport measurement for sample FPC1.

    (A) Rxx curves in an FGT/graphite/FGT device at different temperatures. (B) Corresponding Rxy(B) curves at different temperatures. Scale bar, 3 Ω. (C) Temperature dependence of ΔRxx/Rxx values. The error bars are defined by the noise level. a.u., arbitrary units.

  • Fig. 3 Angular-dependent transport measurements for sample FPC1 at 20 K.

    (A) Rxx(B) curves of an FGT/graphite/FGT device at different tilt angles at 20 K. 0° means the magnetic field perpendicular to the sample surface. Scale bar, 1.5 Ω. (B) Corresponding Rxy(B) curves at different tilt angles at 20 K. Scale bar, 4.5 Ω. (C) Rxy(B) curve at 72° (the magnetic moments in the bottom layer flip first with increasing magnetic field). (D) Rxy(B) curve at 0° (the magnetic moments in the top layer flip first with increasing magnetic field).

  • Fig. 4 Current-dependent transport measurements on FPC3 at 100 K.

    (A) Rxx(B) with different current directions. (B) Rxx measured when the top FGT layer faces upward (0°) and downward (180°). (C) Rxx(B) with different magnitudes of current.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/7/eaaw0409/DC1

    Section S1. Ohmic contacts

    Section S2. Dimensions of all FGT/graphite/FGT devices

    Section S3. Transmission electron microscopy (TEM) on the heterostructures

    Section S4. The effect of graphite layer etch and samples with weak interlayer coupling

    Section S5. Fabrication of a symmetric Hall bar device based on FIB milling

    Section S6. Transport measurement for other samples

    Section S7. Tentative resistor model

    Section S8. Band structure calculation

    Section S9. Discussion about the angle-dependent results in Fig. 3

    Fig. S1. Ohmic contact confirmation.

    Fig. S2. TEM on FGT/graphite/FGT heterostructure.

    Fig. S3. The effect of graphite layer etch and samples with weak interlayer coupling.

    Fig. S4. Rxx and Rxy of an FIB-etched FGT/graphite/FGT device at 50 K.

    Fig. S5. Measurements for FPC1 and FPC9.

    Fig. S6. Measurement for an asymmetric sample FPC2 (the anomalous Hall signal is large).

    Fig. S7. Angle-dependent curves at 50 K for sample FPC11, with top and bottom FGT touching each other.

    Fig. S8. Rxx(B) and Rxy(B) curves for two samples with relatively larger ΔRxx/Rxx value at 50 K.

    Fig. S9. Tentative resistor model.

    Fig. S10. Surface states and surface spin texture of FGT.

    Table S1. Dimensions of all FGT/graphite/FGT devices.

  • Supplementary Materials

    This PDF file includes:

    • Section S1. Ohmic contacts
    • Section S2. Dimensions of all FGT/graphite/FGT devices
    • Section S3. Transmission electron microscopy (TEM) on the heterostructures
    • Section S4. The effect of graphite layer etch and samples with weak interlayer coupling
    • Section S5. Fabrication of a symmetric Hall bar device based on FIB milling
    • Section S6. Transport measurement for other samples
    • Section S7. Tentative resistor model
    • Section S8. Band structure calculation
    • Section S9. Discussion about the angle-dependent results in Fig. 3
    • Fig. S1. Ohmic contact confirmation.
    • Fig. S2. TEM on FGT/graphite/FGT heterostructure.
    • Fig. S3. The effect of graphite layer etch and samples with weak interlayer coupling.
    • Fig. S4. Rxx and Rxy of an FIB-etched FGT/graphite/FGT device at 50 K.
    • Fig. S5. Measurements for FPC1 and FPC9.
    • Fig. S6. Measurement for an asymmetric sample FPC2 (the anomalous Hall signal is large).
    • Fig. S7. Angle-dependent curves at 50 K for sample FPC11, with top and bottom FGT touching each other.
    • Fig. S8. Rxx(B) and Rxy (B) curves for two samples with relatively larger ΔRxx/Rxx value at 50 K.
    • Fig. S9. Tentative resistor model.
    • Fig. S10. Surface states and surface spin texture of FGT.
    • Table S1. Dimensions of all FGT/graphite/FGT devices.

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