Irreversible magnetic-field dependence of ferromagnetic resonance and inverse spin Hall effect voltage in CoFeB/Pt bilayer

• Hysteretic behavior of ferromagnetic resonance spectra in the CoFeB/Pt sample.
• Hysteretic behavior of inverse-spin Hall effect voltage in the CoFeB/Pt sample.
• Proportion of inverse spin-Hall effect voltage can be determined by the cavity mode.
• The hysteretic behavior arise from the unsaturated magnetization limit.
• The well-defined spin Hall angle which consider a hysteresis can be obtained.

Magnetic field (H) sweeping direction dependences of the mixed voltage Vmix induced by the inverse-spin Hall effect(ISHE) and spin-rectified effect (SRE) in a CoFeB (5 nm)/Pt (10 nm) bilayer structure are investigated using the ferromagnetic resonance in the TE mode cavities and coplanar waveguide methods. Conventionally, the magnitude of ISHE voltage VISH (symmetric) excluding the SRE (antisymmetric component) was unavoidably separated from the fitting curve of Vmix (a sum of a symmetric and an antisymmetric part) for one direction of H-source. By studying the ratio of the two voltage parts with the bi-directional H sweeping, the optimized VISH (no SRE condition) value which also include a well-defined spin Hall angle can be obtained via the linear response relation of ISHE and SRE components.