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Current-controlled periodic double-polarity reversals in a spin-torque vortex oscillator.
Chloé Chopin1, Simon de Wergifosse1, Anatole Moureaux1
1Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, Place Croix du Sud 1, 1348, Louvain-la-Neuve, Belgium.
Scientific Reports
|October 15, 2024
Summary
Spin-torque vortex oscillators exhibit confined gyration amplitudes due to periodic polarity reversals. This non-linear behavior, controlled by current density and chirality, shows potential for neuromorphic computing applications.
Area of Science:
- Spintronics
- Nonlinear Dynamics
- Computational Physics
Background:
- Spin-torque vortex oscillators are devices that utilize the spin transfer torque phenomenon.
- Vortex core dynamics in magnetic systems are crucial for understanding their behavior.
- Previous studies have explored vortex core motion but not this specific confinement regime.
Purpose of the Study:
- To investigate the micromagnetic behavior of a spin-torque vortex oscillator under out-of-plane dc current excitation.
- To analyze the confinement of the vortex core gyration amplitude.
- To explore the potential of this phenomenon for neuromorphic applications.
Main Methods:
- Micromagnetic simulations were employed to model the spin-torque vortex oscillator.
- The simulations focused on the dynamics of the vortex core under varying current densities.
- Vortex core polarity reversals and their impact on gyration orbits were analyzed.
Main Results:
- A confinement regime for the vortex core gyration amplitude was identified, bounded by two distinct orbits.
- This confinement arises from periodical double vortex core polarity reversals.
- The frequency and limits of gyration are tunable via input current density, with chirality influencing the regime's appearance.
Conclusions:
- The spin-torque vortex oscillator exhibits a non-linear regime with confined vortex core gyration.
- This confinement is a result of a periodic double polarity reversal mechanism.
- The tunable non-linear dynamics make these oscillators promising candidates for neuromorphic computing, such as leaky integrate-and-fire neurons.
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