Spin torque oscillations triggered by in-plane field

We study the dynamics of a spin torque nano oscillator that consists of parallelly magnetized free and pinned layers by numerically solving the associated Landau-Lifshitz-Gilbert-Slonczewski equation in the presence of a field-like torque. We observe that an in-plane magnetic field which is applied for a short interval of time (<1 ns) triggers the magnetization to exhibit self-oscillations from low energy initial magnetization state. Also, we confirm that the frequency of oscillations can be tuned over the range similar to 25-similar to 72 GHz by current, even in the absence of field-like torque. We find the frequency enhancement up to 10 GHz by the presence of field-like torque. We determine the Q-factor for different frequencies and show that it increases with frequency. Our analysis with thermal noise confirms that the system is stable against thermal noise and the dynamics is not altered appreciably by it.

Automated summary

We studied the dynamics of a spin torque nano oscillator and found that a short duration in-plane magnetic field can trigger self-oscillations of magnetization. The oscillation frequency can be tuned by current, even without a field-like torque, and field-like torque can enhance the frequency. Our analysis shows that the Q-factor increases with frequency. The system is stable against thermal noise and its dynamics are not significantly affected by it.