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Publication Citation: Spin-transfer dynamics in spin valves with out-of-plane magnetized CoNi free layers

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Author(s): William H. Rippard; Alina M. Deac; Matthew R. Pufall; Justin M. Shaw; Mark W. Keller; Stephen E. Russek; Gerrit E. Bauer; Claudio Serpico;
Title: Spin-transfer dynamics in spin valves with out-of-plane magnetized CoNi free layers
Published: January 29, 2010
Abstract: We have measured spin-transfer-induced dynamics in magnetic nanocontact devices having a perpendicularly magnetized Co/Ni free layer and an in-plane magnetized CoFe fixed layer. The frequencies and powers of the excitations agree well with the predictions of the single-domain model and indicate that the excited dynamics correspond to precessional orbits with angles ranging from zero to 90° as the applied current is increased at a fixed field. From measurements of the onset current as a function of applied field strength we estimate the magnitude of the spin torque asymmetry parameter λ{approximately equal}1.5. By combining these with spin torque ferromagnetic resonance measurements, we also estimate the spin-wave radiation loss in these devices.
Citation: Physical Review B
Volume: 81
Pages: pp. 014426-1 - 014426-8
Keywords: magnetics;spin electronics;magnetodynamics;nanomagnetics
Research Areas: Physics, Condensed Matter Physics, Electron Physics