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A 20 nm spin Hall nano-oscillator
Philipp Dürrenfeld1, Ahmad A Awad2, Afshin Houshang2
1School of Electronic Science and Engineering, Nanjing University, 210093 Nanjing, China. pduerrenfeld@nju.edu.cn and Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden.
Nanoscale
|January 6, 2017
Summary
Researchers developed tiny Spin Hall nano-oscillators (SHNOs) using 20 nm constrictions. These nanoscopic devices operate at low currents, showing improved efficiency and unique positive current tunability for microwave signal generation.
Area of Science:
- Spintronics
- Nanotechnology
- Microwave signal generation
Background:
- Spin Hall nano-oscillators (SHNOs) are promising microwave signal generators driven by pure spin currents.
- Scaling down SHNOs is crucial for developing advanced spintronic devices.
- Previous studies often observed negative current tunability in localized magnetic excitations.
Purpose of the Study:
- To demonstrate the fabrication and operation of nanoscopic SHNOs.
- To investigate the impact of lateral confinement on SHNO performance and current tunability.
- To explore the potential for ultra-low operating currents and improved power efficiency in scaled-down SHNOs.
Main Methods:
- Fabrication of 20 nm nano-constrictions in Platinum/Nickel-Iron (Pt/NiFe) bilayers.
- Experimental characterization of SHNO performance, including operating currents and power conversion efficiency.
- Micromagnetic simulations to analyze magnetic dynamics and understand tunability mechanisms.
Main Results:
- Successfully scaled SHNOs down to nanoscopic dimensions (20 nm constrictions).
- Achieved ultra-low operating currents and enhanced power conversion efficiency.
- Observed a positive current tunability, attributed to the interplay of shape and demagnetizing fields within the nano-constriction.
Conclusions:
- Nanoscopic SHNOs are feasible and offer significant advantages in terms of operating current and efficiency.
- Lateral confinement in nano-constrictions induces unique magnetic field effects, leading to positive current tunability.
- The active spin-torque dynamics extend beyond the physical constriction, influencing device performance.
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