Frequency Modulation of a Nano-Oxide Layer-Based Spin-Torque Oscillator With FeCo Nanocontacts

Author

Al-Mahdawi, Muftah ; Doi, M. ; Hashimoto, Shuji ; Fuke, Hiromi N. ; Iwasaki, Hisao ; Sahashi, Masashi

Author_Institution

Dept. of Electron. Eng., Tohoku Univ., Sendai, Japan

Volume

47

Issue

10

fYear

2011

Firstpage

3380

Lastpage

3382

Abstract

We studied the effect of injecting a low-frequency (0.5-1 GHz) ac signal on the natural oscillations of a nano-oxide layer-based nanocontact magnetoresistive spin-torque oscillator with multiple Fe₅₀Co₅₀ nanocontacts. We observed a frequency modulation effect with odd-numbered side bands having low amplitudes. Also, no frequency shift at main spectral peak´s frequency, typical with nonlinear frequency modulation, was observed. We could not completely explain this behavior, but we propose that this could be related to the internal dynamics of constricted domain walls.

Keywords

cobalt alloys; ferromagnetic materials; frequency modulation; iron alloys; magnetic domain walls; magnetoresistive devices; nanocontacts; nanomagnetics; radiofrequency oscillators; torque; Fe₅₀Co₅₀; constricted domain walls; frequency 0.5 GHz to 1 GHz; frequency modulation effect; internal dynamics; nano-oxide layer-based spin-torque oscillator; nanocontact magnetoresistive spin-torque oscillator; nanocontacts; nonlinear frequency modulation; spectral peak frequency; Frequency modulation; Magnetic multilayers; Magnetic resonance; Magnetoresistance; Microwave oscillators; Nanocontacts; Ferromagnetic nanocontact (NC); frequency modulation; magnetoresistance (MR); spin-torque oscillator; spin-transfer torque (STT);

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.2011.2159104

Filename

6027594