Phase Locked Loop of the Spin-Torque Nanooscillator
  We have studied the dynamics of a spin-torque nanooscillator's (STNO) phase locked loop (PLL) generating microwave oscillations in a broad range of frequencies under the effect of direct current and external magnetic field. Bifurcations in the system caused by a change in the frequency detuning of synchronized oscillations are considered. Bands of phase locking and synchronism are determined. The existence of a phase locking band in the filterless PLL of STNOs basically distinguishes these oscillators from other types of microwave generators. 
Alexander A. Mitrofanov, Ansar R. Safin, and Nicolay N. Udalov
nlin.CD cond-mat.mes-hall