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Magnetic Tweezers for the Measurement of Twist and Torque
Published on: May 19, 2014
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Element-Specific Detection of Sub-Nanosecond Spin-Transfer Torque in a Nanomagnet Ensemble
Satoru Emori1, Christoph Klewe2, Jan-Michael Schmalhorst3
1Department of Physics, Virginia Tech, Blacksburg, Virginia 24061, United States.
Nano Letters
|October 21, 2020
Summary
Spin-transfer torque manipulates magnetic nanomagnets even with low net magnetization. This torque becomes stronger as net magnetization decreases, offering subnanosecond control of nanomagnet ensembles.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Nanotechnology
Background:
- Spin currents can induce spin-transfer torques (STTs) in magnetic systems.
- Recent studies demonstrated STTs in antiferromagnets, even with vanishing net magnetization.
- Understanding STTs in nanomagnet ensembles is crucial for advanced spintronic devices.
Purpose of the Study:
- To experimentally demonstrate the operation of spin-transfer torque in a macroscopic ensemble of randomly magnetized Co nanomagnets.
- To investigate the dependence of STT strength on the net magnetization of the nanomagnet ensemble.
- To explore the potential of STTs for ultrafast manipulation of nanomagnet states.
Main Methods:
- Utilized element- and time-resolved X-ray ferromagnetic resonance (XFMR) spectroscopy.
- Directly detected subnanosecond dynamics of Co nanomagnets.
- Excited nanomagnets into precession using an oscillating spin current.
Main Results:
- Confirmed the operation of spin-transfer torque in a macroscopic ensemble of Co nanomagnets.
- Observed that STT strength increases relative to magnetic field torques as net magnetization decreases.
- Characterized subnanosecond precession dynamics of the nanomagnets.
Conclusions:
- Spin-transfer torque is effective in manipulating weakly interacting, randomly magnetized nanomagnet ensembles.
- STTs provide a viable mechanism for controlling nanomagnet states on subnanosecond timescales.
- Findings suggest STTs as a promising tool for future spintronic applications requiring fast switching.
Keywords:
X-ray magnetic circular dichroismferromagnetic resonancemagnetic nanoparticlesspin pumpingspin-transfer torqueMore Related Videos
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