Spin-transfer-torque resonant switching and injection locking in presence of a weak external microwave field for spin valves with perpendicular materials

Abstract

The effects of a weak microwave field in the magnetization dynamics driven by spin-transfer-torque in spin-valves with perpendicular materials have been systematically studied by means of full micromagnetic simulations. In the system we studied, depending on the working point (bias field and current) in the dynamical stability diagram, we observe either resonant switching and injection locking. The resonant switching, observed in the switching region, occurs when the field frequency is approaching the frequency of the main pre-switching mode giving rise to an asymmetric power distribution of that mode in the sectional area of the free layer. At the resonant frequency, the switching time is weakly dependent on the relative phase between the instant when the current pulse is applied and the microwave field. The injection locking, observed in the dynamical region, is characterized by the following properties: (i) a locking bandwidth which is linearly dependent on the force locking, and (ii) a locking for integer harmonics of the self-oscillation frequency. We compare our numerical results with analytical theory for non-autonomous non-linear system obtaining a good agreement in the current region where the oscillation frequency and output power are characterized from a linear relationship.

References in corpus (14)

• Generation linewidth of an auto-oscillator with a nonlinear frequency shift: Spin-torque nano-oscillator
• Spin-torque switching: Fokker-Planck rate calculation
• Coupling efficiency for phase locking of a spin transfer oscillator to a microwave current
• An Effective Reduction of Critical Current for Current-Induced Magnetization Switching by a Ru Layer Insertion in an Exchange-Biased Spin-Valve
• Lineshape distortion in a nonlinear auto-oscillator near generation threshold: Application to spin-torque nano-oscillators
• Single-shot time-domain studies of spin-torque-driven switching in magnetic tunnel junctions
• Experimental Test of Analytic Theory of Spin Torque Oscillator Dynamics
• Distribution of the magnetization reversal duration in sub-ns spin-transfer switching
• Resonant Spin-Transfer-Driven Switching of Magnetic Devices Assisted by Microwave Current Pulses
• Measurement of nonlinear frequency shift coefficient in spin-torque oscillators based on MgO tunnel junctions
• Spin-torque driven magnetic vortex self-oscillations in perpendicular magnetic fields
• Enhancement in spin-torque efficiency by nonuniform spin current generated within a tapered nanopillar spin valve
• Time domain study of frequency-power correlation in spin-torque oscillators
• Effects of rf Current on Spin Transfer Torque Induced Dynamics

Cited by in corpus (12)

• Spin transfer nano-oscillators
• Influence of the Dzyaloshinskii-Moriya interaction on the spin-torque diode effect
• Magnetization switching by current and microwaves
• Non-Adlerian phase slip and non stationary synchronization of spin-torque oscillators to a microwave source
• Dynamical properties of three terminal magnetic tunnel junctions: spintronics meets spin-orbitronics
• Intrinsic synchronization of an array of spin-torque oscillators driven by the spin-Hall effect
• Current-induced synchronized switching of magnetization
• Enhanced synchronization in an array of spin torque nano oscillators in the presence of oscillating external magnetic field
• Injection locking at zero field in two free layer spin-valves
• Micromagnetic study of electrical-field-assisted magnetization switching in MTJ devices
• Voltage Controlled Magnetic Anisotropy Based Low Energy Switching of a Ferromagnet on a Topological Insulator
• Chirp spectroscopy applied to the characterization of Ferromagnetic Resonance in Magnetic Tunnel Junctions