Nonlinear dynamics near exceptional points of synthetic antiferromagnetic spin-torque oscillators

We consider a synthetic antiferromagnetic spin-torque oscillator (STO) with anisotropic interlayer exchange coupling. This system exhibits exceptional points (EPs) in its linearized dynamics. We find the nonlinear dynamics and the dynamical phase diagram of the system both analytically and numerically. Moreover, we show that, near one of the EPs, the power of the oscillator depends extremely sensitively on the injected spin current. Our findings may be useful for designing sensitive magnetometers and for other applications of STOs.