Designing Magnetic Droplet Soliton Nucleation Employing Spin Polarizer

Abstract

We show by means of micromagnetic simulations that spin polarizer in nano-contact spin torque oscillators (NC-STOs) as the representative of the fixed layer in an orthogonal pseudo-spin valve (P-SV) can be employed to design and to control magnetic droplet soliton nucleation and dynamics. We found that using a tilted spin polarizer layer decreases the droplet nucleation time which is more suitable for high speed applications. However, a tilted spin polarizer increases the nucleation current and decreases the frequency stability of the droplet. Additionally, by driving the magnetization inhomogenously at the nano-contact region, it is found that a tilted spin polarizer reduces the precession angle of the droplet and through an interplay with the Oersted field of the DC current, it breaks the spatial symmetry of the droplet profile. Our findings explore fundamental insight into nano-scale magnetic droplet soliton dynamics with potential tunability parameters for future microwave electronics.