Title :
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
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);
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2011.2159104
