Spin-torque driven magnetic vortex self-oscillations in perpendicular magnetic fields

Abstract

We have employed complete micromagnetic simulations to analyze dc current driven self-oscillations of a vortex core in a spin-valve nanopillar in a perpendicular field by including the coupled effect of the spin-torque and the magnetostatic field computed self-consistently for the entire spin-valve. The vortex in the thicker nanomagnet moves along a quasi-elliptical trajectory that expands with applied current, resulting in blue-shifting of the frequency, while the magnetization of the thinner nanomagnet is non-uniform due to the bias current. The simulations explain the experimental magnetoresistance-field hysteresis loop and yield good agreement with the measured frequency vs. current behavior of this spin-torque vortex oscillator.

10 pages, 3 figures, to be appear on APL

References in corpus (5)

• Current-driven vortex oscillations in metallic nanocontacts
• Strong linewidth variation for spin-torque nano-oscillators as a function of in-plane magnetic field angle
• Spin-Torque-Induced Rotational Dynamics of a Magnetic Vortex Dipole
• Spin-torque driven magnetic vortex self-oscillations in perpendicular magnetic fields
• Micromagnetic simulations of persistent oscillatory modes excited by spin-polarized current in nanoscale exchange-biased spin valves

Cited by in corpus (7)

• Spin transfer nano-oscillators
• Micromagnetic understanding of stochastic resonance driven by spin-transfertorque
• Spin-transfer-torque resonant switching and injection locking in presence of a weak external microwave field for spin valves with perpendicular materials
• Spin-torque driven magnetic vortex self-oscillations in perpendicular magnetic fields
• Field-Free Synthetic-Ferromagnet Spin Torque Oscillator
• Frequency enhancement and power tunability in tilted polarizer spin-torque nano oscillator
• Injection locking at zero field in two free layer spin-valves