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Scanning SQUID Study of Vortex Manipulation by Local Contact
Published on: February 1, 2017
Direct determination of large spin-torque nonadiabaticity in vortex core dynamics
1Fachbereich Physik, Universität Konstanz, Universitätsstrasse 10, D-78457 Konstanz, Germany.
Physical Review Letters
|January 15, 2011
Summary
We imaged vortex core displacement in Permalloy discs using spin-torque. Our findings quantify the nonadiabatic spin torque, revealing strong nonadiabatic transport in these magnetic structures.
Area of Science:
- Spintronics
- Condensed Matter Physics
- Materials Science
Background:
- Vortex core dynamics in magnetic nanostructures are crucial for device applications.
- Spin-torque effects are key drivers of magnetic switching.
- Understanding nonadiabatic spin torque is essential for advanced spintronic devices.
Purpose of the Study:
- To unambiguously determine spin torques acting on vortex cores.
- To quantify the amplitude of the nonadiabatic spin torque.
- To investigate nonadiabatic transport in magnetic vortex spin structures.
Main Methods:
- Pump-probe photoemission electron microscopy (PEEM) was employed.
- Imaging of vortex core displacement in Permalloy discs.
- Exploitation of symmetry differences between spin torques and Oersted-field torque.
Main Results:
- Spin torques and Oersted-field torque were unambiguously determined.
- The nonadiabaticity parameter was quantified as β=0.15±0.07.
- Nonadiabaticity was found to be significantly larger than the damping constant (α).
Conclusions:
- Strong nonadiabatic transport occurs across high magnetization gradient vortex spin structures.
- The quantified nonadiabatic spin torque is substantial.
- This work provides critical insights into spin-torque dynamics in magnetic vortices.
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