High frequency operation of a spin-torque oscillator at low field

Authors

  • S. M. Mohseni,

    Corresponding author
    1. Materials Physics, School of Information and Communication Technology, KTH Royal Institute of Technology, Electrum 229, 164 40 Kista, Sweden
    2. NanOsc AB, Electrum 205, 164 40 Kista, Sweden
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  • S. R. Sani,

    1. Materials Physics, School of Information and Communication Technology, KTH Royal Institute of Technology, Electrum 229, 164 40 Kista, Sweden
    2. NanOsc AB, Electrum 205, 164 40 Kista, Sweden
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  • J. Persson,

    1. NanOsc AB, Electrum 205, 164 40 Kista, Sweden
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  • T. N. Anh Nguyen,

    1. Materials Physics, School of Information and Communication Technology, KTH Royal Institute of Technology, Electrum 229, 164 40 Kista, Sweden
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  • S. Chung,

    1. Materials Physics, School of Information and Communication Technology, KTH Royal Institute of Technology, Electrum 229, 164 40 Kista, Sweden
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  • Ye. Pogoryelov,

    1. Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden
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  • Johan Åkerman

    1. Materials Physics, School of Information and Communication Technology, KTH Royal Institute of Technology, Electrum 229, 164 40 Kista, Sweden
    2. NanOsc AB, Electrum 205, 164 40 Kista, Sweden
    3. Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden
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Abstract

We demonstrate a nano-contact based spin-torque oscillator (STO) combining a high operating frequency with low field operation. The STO is based on an orthogonal spin-valve architecture with an in-plane Co polarizer and an out-of-plane Co/Ni multilayer free layer. High frequency operation at low external fields is achieved by tailoring the Co/Ni layer properties to increase the strength (Hk) of the perpendicular magnetic anisotropy, while simultaneously reducing the saturation magnetization (Ms). Our approach emphasizes the importance of μ0(Hk–Ms) in determining the operating frequency in this system, and suggests that yet higher frequencies should be attainable through further optimization.

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(© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

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