Micromagnetic study of a spin-torque oscillator based on a magnetic nano-contact magnetized at an arbitrary angle

摘要

The nature of spin wave modes excited by spin-polarized direct current in aspin-torque auto-oscillator based on a magnetic nanocontact was studied by amicromagnetic simulation in the case when the external bias magnetic field wasrotated from the in-plane to perpendicular-to-plane orientation. In qualitativeagreement with the weakly-nonlinear analytical theory it was found, that at acertain critical angle, an abrupt switching from the self-localized nonlinear"bullet" mode to a propagating quasi-linear Slonczewski mode takes place, andis accompanied by an upward jump in generated microwave frequency. It was,also, found that the analytical theory overestimates the magnitude of acritical magnetization angle, corresponding to the mode switching, and that themagnitude of the frequency jump caused by the mode switching is inverselyproportional to the nanocontact radius.