Non-Adlerian phase slip and non-stationary synchronization of spin-torque oscillators to a microwave source

The non-autonomous dynamics of spin-torque oscillators in presence of both microwave current and field at the same frequency can exhibit complex non-isochronous effects [1-2]. Here, a non-stationary mode hopping between quasi-periodic (frequency pulling) and periodic mode (phase locking), and a deterministic phase slip characterized by an oscillatory synchronization transient (non- Adlerian phase slip) after the phase jump of have been predicted in an exchange biased spin-valves composed by IrMn(8nm)/Py(10nm)/Cu(10nm)/Py(4nm) with elliptical area (120x60 nm2).