Time domain mapping of spin torque oscillator effective energy.
- Author(s): Rowlands, Graham E
- Katine, Jordan A
- Langer, Juergen
- Zhu, Jian
- Krivorotov, Ilya N
- et al.
Published Web Locationhttps://doi.org/10.1103/physrevlett.111.087206
Stochastic dynamics of spin torque oscillators can be described in terms of magnetization drift and diffusion over a current-dependent effective energy surface given by the Fokker-Planck equation. Here we present a method that directly probes this effective energy surface via time-resolved measurements of the microwave voltage generated by a spin torque oscillator. We show that the effective energy approach provides a simple recipe for predicting spectral linewidths and line shapes near the generation threshold. Our time domain technique also accurately measures the fieldlike component of spin torque in a wide range of the voltage bias values.