Linear Phase Tuning of Spin Torque Oscillators Using In-Plane Microwave Fields

Author

Tui Zeng ; Yan Zhou ; Akerman, J. ; Lai, P.T. ; Pong, Philip W. T.

Author_Institution

Dept. of Electr. & Electron. Eng., Univ. of Hong Kong, Hong Kong, China

Volume

50

Issue

1

fYear

2014

fDate

Jan. 2014

Firstpage

1

Lastpage

4

Abstract

We demonstrate numerically and analytically that a nano-pillar spin torque oscillator (STO), operating either with in-plane or out-of-plane free-layer precession, locks to a microwave field (H_ac) having the same frequency as the STO. By varying the spatial direction of the microwave field, we further show the preferred phase shift (ΔΦ₀) between the STO and H_ac can be tuned in a linear fashion. We explain this phenomenon by using a magnetic-energy-based analysis. Our results provide a way to synchronize serially connected STOs by tuning the phase shift of each individual STO with external microwave field, which may enhance the locking efficiency, the locking range, and the output power of the serially connected STOs.

Keywords

microwave oscillators; numerical analysis; phase locked oscillators; in-plane free-layer precession; in-plane microwave fields; linear phase tuning; locking efficiency; magnetic-energy-based analysis; nanopillar spin torque oscillator; numerical analysis; out-of-plane free-layer precession; preferred phase shift; serially connected spin torque oscillators; Magnetization; Microwave oscillators; Orbits; Perpendicular magnetic anisotropy; Torque; Locking frequency; microwave field; phase lock; spin torque oscillator;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.2013.2276665

Filename

6693030