Author: ["V. S. Pribiag","I. N. Krivorotov","G. D. Fuchs","P. M. Braganca","O. Ozatay","J. C. Sankey","D. C. Ralph","R. A. Buhrman"]
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Abstract
Transfer of angular momentum from a spin-polarized current to a ferromagnet provides an efficient means to control the magnetization dynamics of nanomagnets. A peculiar consequence of this spin torque, the ability to induce persistent oscillations in a nanomagnet by applying a d.c. current, has previously been reported only for spatially uniform nanomagnets. Here, we demonstrate that a quintessentially non-uniform magnetic structure, a magnetic vortex, isolated within a nanoscale spin-valve structure, can be excited into persistent microwave-frequency oscillations by a spin-polarized d.c. current. Comparison with micromagnetic simulations leads to identification of the oscillations with a precession of the vortex core. The oscillations, which can be obtained in essentially zero magnetic field, exhibit linewidths that can be narrower than 300 kHz at ∼1.1 GHz, making these highly compact spin-torque vortex-oscillator devices potential candidates for microwave signal-processing applications, and a powerful new tool for fundamental studies of vortex dynamics in magnetic nanostructures.Cite this article
Pribiag, V., Krivorotov, I., Fuchs, G. et al. Magnetic vortex oscillator driven by d.c. spin-polarized current. Nature Phys 3, 498–503 (2007). https://doi.org/10.1038/nphys619 