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Magnetic memory driven by topological insulators
Hao Wu1, Aitian Chen2, Peng Zhang3
1Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, CA, 90095, USA. wuhaophysics@ucla.edu.
Nature Communications
|October 30, 2021
Summary
Giant spin-orbit torque from topological insulators offers efficient magnetic memory writing. This study demonstrates a functional device achieving high TMR and low switching current, paving the way for advanced SOT-MRAM.
Area of Science:
- Spintronics
- Quantum Materials
- Condensed Matter Physics
Background:
- Topological insulators (TIs) offer giant spin-orbit torque (SOT) for energy-efficient magnetic memory.
- Integration challenges with magnetic tunnel junctions (MTJs) have limited practical applications.
Purpose of the Study:
- To demonstrate a functional TI-MTJ device for energy-efficient spintronic devices.
- To lay the foundation for SOT-based magnetic random-access memory (SOT-MRAM) using topological insulators.
Main Methods:
- Fabrication and characterization of a TI-MTJ device.
- Quantification of charge-spin conversion efficiency (θSH) using SOT-induced magnetic switching field shift and ST-FMR.
Main Results:
- Achieved a state-of-the-art tunneling magnetoresistance (TMR) ratio of 102%.
- Demonstrated an ultralow switching current density of 1.2 × 10^5 A cm^-2 at room temperature.
- Quantified charge-spin conversion efficiency (θSH) in TIs as 1.59 and 1.02, one order of magnitude higher than heavy metals.
Conclusions:
- The developed TI-MTJ device is a core element for future energy-efficient SOT-MRAM.
- High TIs' charge-spin conversion efficiency enables a significant reduction in energy consumption for spintronic devices.
- This work inspires a shift towards quantum materials for next-generation SOT-MRAM.
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