CoFeB-Based Spin Hall Nano-Oscillators

Authors :: T. Q. Le
Ezio Iacocca
Ahmad A. Awad
Mojtaba Ranjbar
Mohammad Haidar
Johan Åkerman
Masoumeh Fazlali
Afshin Houshang
Philipp Dürrenfeld
M. Balinskiy
Randy K. Dumas
Source :: IEEE Magnetics Letters. 5:1-4
Publication Year :: 2014
Publisher :: Institute of Electrical and Electronics Engineers (IEEE), 2014.
Abstract: We demonstrate magnetization auto-oscillations driven by pure spin currents in spin Hall nano-oscillators based on CoFeB/Pt bilayers. Despite the very low anisotropic magnetoresistance of CoFeB, a substantial microwave signal power can be detected, even at room temperature, indicating that a sizable spin wave amplitude is generated. Spin torque ferromagnetic resonance measurements reveal that the generated auto-oscillation frequency lies below the ferromagnetic resonance frequency of CoFeB and is therefore well described by a self-localized spin wave bullet mode.