We report on the fabrication of nano-contact spin-torque oscillators based on single layers of the epitaxially grown half-metal NiMnSb with ultralow spin wave damping. We demonstrate magnetization auto-oscillations at microwave frequencies in the 1–3 GHz range in out-of-plane magnetic fields. Threshold current densities as low as 3 × 1011 A m−2 are observed as well as minimum oscillation linewidths of 200 kHz, both of which are much lower than the values achieved in conventional metallic spin-valve-based devices of comparable dimensions. These results enable the fabrication of spin transfer torque driven magnonic devices with low current density requirements, improved signal linewidths, and in a simplified single-layer geometry.
Low-current, narrow-linewidth microwave signal generation in NiMnSb based single-layer nanocontact spin-torque oscillators
Present address: School of Electronic Science and Engineering, Nanjing University, 210093 Nanjing, China.
Present address: School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287, USA.
P. Dürrenfeld, F. Gerhard, S. M. Mohseni, M. Ranjbar, S. R. Sani, S. Chung, C. Gould, L. W. Molenkamp, J. Åkerman; Low-current, narrow-linewidth microwave signal generation in NiMnSb based single-layer nanocontact spin-torque oscillators. Appl. Phys. Lett. 28 November 2016; 109 (22): 222403. https://doi.org/10.1063/1.4968813
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