Spin-torque driven ferromagnetic resonance in a nonlinear regime

Abstract

Spin-valve based nanojunctions incorporating Co|Ni multilayers with perpendicular anisotropy were used to study spin-torque driven ferromagnetic resonance (ST-FMR) in a nonlinear regime. Perpendicular field swept resonance lines were measured under a large amplitude microwave current excitation, which produces a large angle precession of the Co|Ni layer magnetization. With increasing rf power the resonance lines broaden and become asymmetric, with their peak shifting to lower applied field. A nonhysteretic step jump in ST-FMR voltage signal was also observed at high powers. The results are analyzed in in terms of the foldover effect of a forced nonlinear oscillator and compared to macrospin simulations. The ST-FMR nonhysteretic step response may have applications in frequency and amplitude tunable nanoscale field sensors.

4 pages, 3 figures, to appear in Applied Physics Letters

References in corpus (6)

• Spin-transfer-driven ferromagnetic resonance of individual nanomagnets
• Voltage generation by ferromagnetic resonance
• Spin-torque driven ferromagnetic resonance of Co/Ni synthetic layers in spin valves
• Theory of the spin-torque-driven ferromagnetic resonance in a ferromagnet/normal-metal/ferromagnet structure
• Spin torque and waviness in magnetic multilayers: a bridge between Valet-Fert theory and quantum approaches
• Finite size effects on spin-torque driven ferromagnetic resonance in spin-valves with a Co/Ni synthetic free layer

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• Mapping out the spin-wave modes of constriction-based spin Hall nano-oscillators in weak in-plane fields
• Wireless communication between two magnetic tunnel junctions acting as oscillator and diode
• Resonant magneto-acoustic switching: influence of Rayleigh wave frequency and wavevector
• Anomalous Gilbert Damping and Duffing Features of the SFS {\boldmath ${\phi }_0$} Josephson Junction
• Multiscale approach to spin transport in magnetic multilayers
• Dependence of spin torque diode voltage on applied field direction
• Nanoscale Spin Injector Driven by a Microwave Voltage