Research ArticlePHYSICS

Ultrafast magnetization reversal by picosecond electrical pulses

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Science Advances  03 Nov 2017:
Vol. 3, no. 11, e1603117
DOI: 10.1126/sciadv.1603117
  • Fig. 1 Schematic of the CPS device and characterization of electrical pulse.

    (A) Schematic of electrical switching experiment. The photoswitch is illuminated with laser pulses while being biased with a dc source. Magnetization dynamics of GdFeCo is monitored with time-resolved MOKE. Left: Optical image of the photoswitch. During laser illumination, photoexcited carriers in low-temperature GaAs conduct current across the gap, generating a transient electrical pulse propagating in both directions. Right: Optical image of the GdFeCo section of CPS. Scale bars, 20 μm. (B) Calculated temporal current density profile through the GdFeCo section, based on the temporal current profile measured with a Protemics Spike probe positioned 1 mm before the GdFeCo section.

  • Fig. 2 Single-shot optical and electrical switching of GdFeCo.

    (A) Differential MOKE images of bare GdFeCo film after sequential 6.4-ps optical pulse irradiation. Absorbed fluence is 1.8 mJ/cm2. After each optical pulse, the magnetization of GdFeCo toggles to the opposite direction. The contrast indicates change in magnetization. (B) Differential MOKE images of GdFeCo CPS section after sequential 9-ps electrical pulse excitation. After each electrical pulse, the magnetization of GdFeCo toggles. Yellow and blue dashed lines indicate gold CPS and GdFeCo sections, respectively. Scale bars, 5 μm.

  • Fig. 3 Magnetization dynamics of GdFeCo after electrical excitations.

    Electrical demagnetization and switching of GdFeCo. All fluences are calculated absorbed fluences. With increasing electrical pulse amplitude, the GdFeCo demagnetization amplitude increases and eventually switches around 10 ps.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/11/e1603117/DC1

    Supplementary Text

    fig. S1. Magnetic properties of the GdFeCo stack.

    fig. S2. Schematic of the experimental setup for measuring the temporal profile of the electrical pulse.

    fig. S3. Temporal current density profiles in CPS.

    fig. S4. Energy spectral density of the electrical pulse, calculated as the square of the Fourier transform of the electrical pulse in the time domain.

    fig. S5. Frequency-dependent absorption calculation on CPS.

    fig. S6. Evolution of the out-of-plane component of the magnetization after arrival of a 9-ps electrical pulse due to SOTs.

    Reference (43)

  • Supplementary Materials

    This PDF file includes:

    • Supplementary Text
    • fig. S1. Magnetic properties of the GdFeCo stack.
    • fig. S2. Schematic of the experimental setup for measuring the temporal profile of the electrical pulse.
    • fig. S3. Temporal current density profiles in CPS.
    • fig. S4. Energy spectral density of the electrical pulse, calculated as the square of the Fourier transform of the electrical pulse in the time domain.
    • fig. S5. Frequency-dependent absorption calculation on CPS.
    • fig. S6. Evolution of the out-of-plane component of the magnetization after arrival of a 9-ps electrical pulse due to SOTs.
    • Reference (43)

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