Injection Locking of Spin-Torque Nano-Oscillators

We demonstrated the phase locking of a spin-torque oscillator (STO) to an alternating current (ac) using macrospin and micromagnetic simulations. We found that the locking properties of both approaches agree with each other. The phase difference between the STO and the injected ac stabilizes at Δφ ≈ 90° and is not sensitive to the initial phase difference, which provides potential application of STO for microwave generation.