Related Experiment Video
Updated: Feb 3, 2026
09:10
Fabrication and Testing of Microfluidic Optomechanical Oscillators
Published on: May 29, 2014
12.7K
Injection locking of multiple auto-oscillation modes in a tapered nanowire spin Hall oscillator
Kai Wagner1,2, Andrew Smith3, Toni Hache4,5
1Helmholtz-Zentrum Dresden - Rossendorf, Institute of Ion Beam Physics and Materials Research, 01328, Dresden, Germany. k.wagner@hzdr.de.
Scientific Reports
|October 31, 2018
Summary
Spin Hall oscillators (SHO) exhibit two distinct self-localized spin-wave bullets. These bullets can be individually synchronized to external signals, enhancing single-mode operation and tunability.
Area of Science:
- Spintronics
- Condensed Matter Physics
- Nanotechnology
Background:
- Spin Hall oscillators (SHO) are advanced devices for high-frequency signal generation and detection.
- Their electrical, magnetic, and optical readout capabilities, combined with a simple bilayer design, make them highly promising.
- Tapered nanowire structures are explored for novel oscillator behaviors.
Purpose of the Study:
- To experimentally investigate the spatial dependence and spectral properties of auto-oscillations in Pt/NiFe tapered nanowire SHO devices.
- To confirm the existence of multiple self-localized spin-wave bullets predicted by theoretical models.
- To explore the synchronization of these spin-wave bullets with external microwave signals.
Main Methods:
- Fabrication of SHO devices using a Pt(7 nm)/Ni80Fe20(5 nm) bilayer on tapered nanowires.
- Utilizing Brillouin light scattering microscopy for spatial and spectral analysis of auto-oscillations.
- Applying external microwave signals to study synchronization phenomena.
Main Results:
- Observation of two distinct self-localized spin-wave bullets oscillating at 5.2 GHz and 5.45 GHz, spatially separated by 750 nm.
- Experimental confirmation of a predicted state in tapered SHOs.
- Demonstration of individual synchronization of spin-wave bullets, leading to frequency entrainment, linewidth reduction, and amplitude increase.
- Suppression of parasitic modes upon synchronization, promoting single-mode operation.
Conclusions:
- The findings experimentally validate theoretical predictions of multiple coexisting spin-wave bullets in tapered SHOs.
- Individual synchronization of these bullets offers a pathway to enhanced control over SHO operation.
- This work paves the way for realizing extended SHOs with multiple bullets for broader tunability.
Related Concept Videos
01:30Oscillations In An LC Circuit
3.1K
An idealized LC circuit of zero resistance can oscillate without any source of emf by shifting the energy stored in the circuit between the electric and magnetic fields. In such an LC circuit, if the capacitor contains a charge q before the switch is closed, then all the energy of the circuit is initially stored in the electric field of the capacitor. This energy is given by
3.1K
01:06Forced Oscillations
8.0K
When an oscillator is forced with a periodic driving force, the motion may seem chaotic. The motions of such oscillators are known as transients. After the transients die out, the oscillator reaches a steady state, where the motion is periodic, and the displacement is determined.
8.0K
01:07Damped Oscillations
7.2K
In the real world, oscillations seldom follow true simple harmonic motion. A system that continues its motion indefinitely without losing its amplitude is termed undamped. However, friction of some sort usually dampens the motion, so it fades away or needs more force to continue. For example, a guitar string stops oscillating a few seconds after being plucked. Similarly, one must continually push a swing to keep a child swinging on a playground.
Although friction and other non-conservative...
Although friction and other non-conservative...
7.2K
01:04Oscillations about an Equilibrium Position
7.0K
Stability is an important concept in oscillation. If an equilibrium point is stable, a slight disturbance of an object that is initially at the stable equilibrium point will cause the object to oscillate around that point. For an unstable equilibrium point, if the object is disturbed slightly, it will not return to the equilibrium point. There are three conditions for equilibrium points—stable, unstable, and half-stable. A half-stable equilibrium point is also unstable, but is named so...
7.0K
01:19Limits with Oscillating Discontinuities
466
An oscillating discontinuity is a type of discontinuity in which a function’s values fluctuate infinitely often as the input approaches a particular point. Unlike jump discontinuities, where the function suddenly shifts between two values, or infinite discontinuities, where the function diverges without bound, an oscillating discontinuity arises from rapid back-and-forth variation. Because the function never stabilizes toward a single value, no finite limit exists at that point.One of the...
466
01:30RLC Circuit as a Damped Oscillator
2.2K
An RLC circuit combines a resistor, inductor, and capacitor, connected in a series or parallel combination.
Consider a series RLC circuit. Here, the presence of resistance in the circuit leads to energy loss due to joule heating in the resistance. Therefore, the total electromagnetic energy in the circuit is no longer constant and decreases with time. Since the magnitude of charge, current, and potential difference continuously decreases, their oscillations are said to be damped. This is...
Consider a series RLC circuit. Here, the presence of resistance in the circuit leads to energy loss due to joule heating in the resistance. Therefore, the total electromagnetic energy in the circuit is no longer constant and decreases with time. Since the magnitude of charge, current, and potential difference continuously decreases, their oscillations are said to be damped. This is...
2.2K