Abstract
Spintronics materials have recently been considered for radio-frequency devices such as oscillators by exploiting the transfer of spin angular momentum between a spin-polarized electrical current and the magnetic nanostructure it passes through. While previous spin-transfer oscillators (STOs) were based on in-plane magnetized structures, here we present the realization of an STO that contains a perpendicular spin current polarizer combined with an in-plane magnetized free layer. This device is characterized by high-frequency oscillations of the free-layer magnetization, consistent with out-of-plane steady-state precessions induced at the threshold current by a spin-transfer torque from perpendicularly polarized electrons. The results are summarized in static and dynamic current–field state diagrams and will be of importance for the design of STOs with enhanced output signals.
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Acknowledgements
This work has been supported by the French national programmes ANVAR No A0503013 and ANR/PNANO MagICO No ANR-05-NANO-044, as well as partially by the EC programme DYNAMICS No HPRN-CT-2002-00289. I.F. acknowledges support from the Institut Carnot funding of CEA/LETI. We thank A. Slavin, V. Tiberkevich and C. Baraduc for stimulating discussions, A. Manchon for simulations on the spin polarization and S. Petit for assistance with transport measurements.
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Houssameddine, D., Ebels, U., Delaët, B. et al. Spin-torque oscillator using a perpendicular polarizer and a planar free layer. Nature Mater 6, 447–453 (2007). https://doi.org/10.1038/nmat1905
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DOI: https://doi.org/10.1038/nmat1905
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