Thermally Assisted Current-Driven Dynamics in Asymmetric Spin Valves

Current-induced steady precessional modes in standard spin valves are usually excited as an interplay of spin-transfer torque, Gilbert damping, and external magnetic field. We propose an asymmetric spin valve, in which the spin current can excite stationary precessional modes also at zero external magnetic field. We also show that finite temperature can induce transitions between different dynamical modes. These transitions, in turn, lead to telegraph noise in magnetoresistance.