Enhancing the Spin-Orbit Torque Efficiency by the Insertion of a Sub-nanometer β-W Layer

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Spin-orbit torque (SOT) efficiency is crucial for spintronics applications.
• Enhancing SOT efficiency is often limited by the trade-off between resistivity and spin Hall ratio.

Purpose of the Study:

• To investigate the impact of sub-nanometer β-tungsten (β-W) intercalation on SOT efficiency.
• To explore methods for improving SOT efficiency beyond conventional limitations.

Main Methods:

• Fabrication of W/Co/Pt thin-film heterostructures with and without β-W intercalation.
• Characterization of magnetic properties and SOT efficiency using electrical measurements.
• Analysis of the correlation between material structure, resistivity, and spin Hall ratio.

Main Results:

• Intercalation of 0.3 nm β-W into α-W/Co/Pt significantly boosted damping-like SOT efficiency per current density by ~296%.
• Achieved a giant damping-like SOT efficiency per electric field, 12.1 times greater than pure β-W.
• Maintained low resistivity comparable to α-W while achieving a high spin Hall ratio.

Conclusions:

• Sub-nanometer β-W intercalation is a highly effective strategy for enhancing SOT efficiency.
• This method overcomes the conventional resistivity-spin Hall ratio trade-off.
• The findings pave the way for developing more energy-efficient SOT devices.