Compensation of nonlinear phase noise in an in-plane-magnetized anisotropic spin-torque oscillator

Abstract

A theory of generation linewidth of a spin-torque oscillator (STO) based on an in-plane-magnetized nano-pillar with an anisotropic “free” magnetic layer has been developed. It is predicted that by choosing the direction of the in-plane bias magnetic field H 0 along the “hard” anisotropy axis of the STO “free” layer and the magnitude of this field to be four times larger than the anisotropy field H A ( H 0 = 4 H A ) it would be possible to compensate the nonlinear phase noise and to achieve the minimum value of the generation linewidth, characteristic for an auto-oscillator without a nonlinear frequency shift.