Transverse and Longitudinal Spin-Torque Ferromagnetic Resonance for Improved Measurement of Spin-Orbit Torque

Modulation of Spin–Orbit Torque from SrRuO3 by Epitaxial‐Strain‐Induced Octahedral Rotation

“…The cos(ϕ B ) term consists of contributions from both the damping‐like torque (τ DL ) and the anomalous Nernst effect ( R ANE ). The sin(2ϕ B ) term with amplitude R x , which has been removed during data processing or sometimes ignored in previous studies, is likely to arise from a thermal gradient along the direction of current [ 45 ] (Note S6, Supporting Information). Figure 3b shows the typical , which can be well fitted using Equation ().…”

“…Figure 3b shows the typical R xy 2ω , which can be well fitted using Equation (2). After removing the constants from the amplitude of the cos(φ B ) term, we plot B M [45] where J SRO is the current density in the SrRuO 3 layer. We find ξ DL,HHV = 0.078, 0.035, and 0.008 at room temperature for SrRuO 3 /Py KTO, STO, and NGO, respectively.…”

“…The results suggest that the SOT generated by SrRuO 3 is predominantly damping-like. Second, we use the in-plane HHV technique [12,[44][45][46] to measure the SOT efficiency in SrRuO 3 (20 nm)/ Py (4 nm) independently, where the SOT efficiency is extracted from the damping-like torque only (see the Experimental Section; Note S5 of the Supporting Information for details). Figure 3a shows a schematic setup of the HHV measurement.…”

Orbital torque in magnetic bilayers

“…The FM layer is passivated with Ta(2)/MgO(2) capping layers unless specified otherwise (see Materials and Methods). For the net SOT measurement, we use the spin-torque ferromagnetic resonance (ST-FMR) technique 28,29,30,31,32 (see Materials and Methods), which is an established method to separately measure the damping-like torque (DLT) [ ∝̂× (̂×̂) and field-like torque (FLT) [ ∝ (̂×̂) components of the SOT, where ̂ is the unit vector along the magnetization direction and ̂ is the direction perpendicular to both directions of current flow (̂) and thickness (̂). From the measured results, we focus only on the sign of the DLT because it reflects the signs of the spin Hall and orbital Hall conductivities.…”

“…The measured voltages are interpreted to magnetic precession angles of less than 0.5 o , corresponding to a linear-response regime. Thus we ignored the contribution in Vs from spin-pumping and inverse SHE 32,51 , which are estimated to be less than 0.2 μV. We also measured the magnetic dead layer thickness from versus , but found that it does not affect the sign and even magnitude of the DLT.…”