Nonlinear analysis of magnetization dynamics excited by spin Hall effect

Abstract

We investigate the possibility of exciting self-oscillation in a perpendicular ferromagnet by the spin Hall effect on the basis of a nonlinear analysis of the Landau-Lifshitz-Gilbert (LLG) equation. In the self-oscillation state, the energy supplied by the spin torque during a precession on a constant energy curve should equal the dissipation due to damping. Also, the current to balance the spin torque and the damping torque in the self-oscillation state should be larger than the critical current to destabilize the initial state. We find that the second condition in the spin Hall system is not satisfied by deriving analytical solutions of the energy supplied by the spin transfer effect and the dissipation due to the damping from the nonlinear LLG equation. This indicates that the self-oscillation of a perpendicular ferromagnet cannot be excited solely by the spin Hall torque.

7pages, 3 figures

References in corpus (8)

• Angular and temperature dependence of current induced spin-orbit effective fields in Ta/CoFeB/MgO nanowires
• Spin-torque switching: Fokker-Planck rate calculation
• Magnonic Charge Pumping via Spin-Orbit Coupling
• Spin Hall phenomenology of magnetic dynamics
• Spin torque switching of an in-plane magnetized system in a thermally activated region
• Enhancement of the Gilbert damping constant due to spin pumping in noncollinear ferromagnet/nonmagnet/ferromagnet trilayer systems
• Spin Torque Oscillators with Thermal Noise: A Constant Energy Orbit Approach
• Linewidth of Power Spectrum Originated from Thermal Noise in Spin Torque Oscillator

Cited by in corpus (6)

• Theoretical condition for switching the magnetization in a perpendicularly magnetized ferromagnet via the spin Hall effect
• Relaxation time and critical slowing down of a spin-torque oscillator
• Dynamic coupling of ferromagnets via spin Hall magnetoresistance
• Switching induced by spin Hall effect in an in-plane magnetized ferromagnet with the easy axis parallel to the current
• Out-of-plane magnetization oscillation in spin Hall device assisted by field-like torque
• Indirect excitation of self-oscillation in perpendicular ferromagnet by spin Hall effect