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Magnetic Tweezers for the Measurement of Twist and Torque
Published on: May 19, 2014
Spin-torque influence on the high-frequency magnetization fluctuations in magnetic tunnel junctions
S Petit1, C Baraduc, C Thirion
1SPINTEC, URA 2512 CEA/CNRS, CEA/Grenoble, 38054 Grenoble Cedex 9, France.
Physical Review Letters
|March 16, 2007
Summary
Spin transfer torque in magnetic tunnel junctions influences magnetization fluctuations. Noise measurements reveal current direction dependence, explained by spin transfer torque effects on ferromagnetic resonance.
Area of Science:
- Condensed Matter Physics
- Spintronics
- Nanotechnology
Background:
- Magnetic tunnel junctions (MTJs) are key components in spintronics devices.
- Understanding magnetization dynamics is crucial for device performance.
- Ferromagnetic resonance (FMR) describes magnetic excitations.
Purpose of the Study:
- To investigate the influence of spin transfer torque on voltage noise in MTJs.
- To analyze the current direction dependence of magnetic noise.
- To model magnetization fluctuations using established dynamics equations.
Main Methods:
- Performed voltage noise measurements in the 3-7 GHz frequency range.
- Biased magnetic tunnel junctions with a direct current (dc).
- Analyzed noise behavior in relation to bias current direction.
Main Results:
- Observed amplification or reduction of magnetic noise associated with FMR excitations.
- Demonstrated a clear dependence of noise modulation on bias current direction.
- Correlated noise changes with the presence and direction of spin transfer torque.
Conclusions:
- Spin transfer torque significantly affects magnetization fluctuations in MTJs.
- The observed noise modulation provides evidence for spin transfer torque's influence on FMR.
- Gilbert dynamics equation, including spin transfer torque, accurately describes the experimental observations.
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