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Figure Captions
Fig. 1. Schematic of the microfabricated GdFeCo/Ta bilayer to measure anormalous Hall
effect (AHE), Spin orbit torque (SOT) switching, and SOT effective fields by flowing a
DC current IDC, pulse current Ipulse, and AC current IAC, respectively.
Fig. 2. AHE loops of Gd24(Fe90Co10)76 and Gd25(Fe90Co10)75 with a width of Hall bar of 6
µm measured by flowing a DC current IDC = 100 µA.
Fig. 3. Gd composition dependence of net magnetization Mnet, effectve anisotropy field
Hkeff, and polar Kerr rotation qK of Gdx(Fe90Co10)100–x. Hkeff was estimated from the
saturation field of the in-plane hysteresis loop, and qK was measured at a wavelength of l
= 700 nm.
Fig. 4. In-plane field Hx dependence of the SOT switching current density Jsw for Ta /
Gdx(Fe90Co10)100–x bilayers with various Gd contents x.
Fig. 5. Typical results of the harmonic measurements of Ta/Gd23(Fe90Co10)77 bilayers under
the AC current density of JAC = 3.2 MA/cm2. Before the measurements, sample was
magnetized +z direction.
Fig. 6. AC current density JAC dependence of (a) damping-like effective field HDL and (b)
field-like effective field HFL estimated for Ta/Gdx(Fe90Co10)100–x bilayers. HDL and HFL
were evaluated under the condition that Mnet of GdFeCo initially pointed in +z direction.
Fig. 7. Gd composition dependence of (a) damping- and field-like effective fields per unit
AC current density (HDL/JAC and HFL/JAC), (b) damping- and field-like torque per unit AC
current density (tDL/JAC and tFL/JAC) in Ta/Gdx(Fe90Co10)100–x bilayers. tDL and tFL were
calculated as tDL = Mnet HDL and tFL = Mnet HFL, respectively. SOTs and SOT effective
fields were evaluated when Mnet pointed +z direction. The compensation composition of
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GdFeCo is shown as a dashed line in the figure.
Fig. 8. Schematic of damping-like and field-like torques, tDL and tFL, respectively, acting
on sub-lattice FeCo magnetization. Spin current injected from the adjacent Ta exerts
torques tDL and tFL to FeCo sub-lattice moment rather than Gd moment.
Fig. 9. In-plane field Hx dependence of the SOT switching current density Jsw for HFL/Jc =
0, 1.5, and –1.5 Oe/(MA/cm2) simulated based on macro-spin model. Hkeff = 2 kOe, HDL/Jc
= –5 Oe, g
1.93 × 107 rad/s·Oe, and a = 0.1 were assumed to simulate the Jsw of
Gd22(Fe90Co10)78/Ta and Gd28(Fe90Co10)72/Ta bilayers.
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Fig.1.
Fig.2.
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Fig.3.
Fig.4.
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Fig.5.
Fig.6.
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Fig.7.
Fig.8.
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Fig.9.
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