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Magnetization dynamics induced by the Rashba effect in ferromagnetic films
Zhizhou Yu1, Jian Chen, Lei Zhang
1Center for Quantum Transport and Thermal Energy Science, School of Physics and Technology, Nanjing Normal University, Nanjing 210023, China.
Nanoscale
|October 2, 2018
Summary
Lateral structural asymmetry in spintronic devices enables current-induced spin-orbit torque to switch magnetization without an external magnetic field. This research explains the underlying physics using first principles calculations and simulations.
Area of Science:
- Spintronics
- Condensed Matter Physics
- Materials Science
Background:
- Current-induced spin-orbit torque offers low-energy spintronic device potential.
- External magnetic fields are typically required for magnetization reversal via spin-orbit torque.
- Recent experiments show field-free magnetization switching in asymmetric Ta/CoFeB/TaOx systems.
Purpose of the Study:
- To investigate the physical mechanisms behind field-free magnetization switching.
- To understand the role of lateral structural asymmetry in spin-orbit torque phenomena.
- To provide theoretical explanations for experimental observations.
Main Methods:
- First principles calculations of interface potential profiles.
- Analysis of Rashba interactions induced by structural asymmetry.
- Derivation of the Landau-Lifshitz-Gilbert equation from a quantum transport perspective.
- Numerical simulations of magnetization dynamics.
Main Results:
- Lateral asymmetry introduces additional Rashba interactions.
- These Rashba interactions can significantly reduce the required external magnetic field for magnetization reversal.
- Simulations confirm magnetization dynamics influenced by Rashba interactions, including those from asymmetry.
Conclusions:
- The study provides microscopic explanations for field-free magnetization switching observed in asymmetric spintronic devices.
- Lateral structural asymmetry is a key factor in enabling efficient spin-orbit torque-driven magnetization manipulation.
- Theoretical insights support the development of advanced, low-power spintronic technologies.
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