High Entropy Alloy Thin Films as Efficient Spin-Orbit Torque Sources for Spintronic Memories

Area of Science:

• Materials Science
• Condensed Matter Physics
• Spintronics

Background:

• High entropy alloys (HEAs) offer unique properties but their spintronic applications are unexplored.
• Developing efficient spin-current generation layers is crucial for spintronic devices.

Purpose of the Study:

• To investigate iridium-based HEAs as spin Hall layers for spintronic applications.
• To evaluate their efficiency in charge-to-spin current conversion and compatibility with magnetic heterostructures.

Main Methods:

• Magnetron sputtering at room temperature to grow iridium-based HEA films.
• Spin-torque ferromagnetic resonance and harmonic Hall measurements to quantify spin-orbit torque.
• Epitaxial growth of magnetic multilayers and synthetic antiferromagnets.

Main Results:

• Iridium-based HEAs demonstrate highly efficient charge-to-spin current conversion.
• Enables epitaxial growth of magnetic multilayers and synthetic antiferromagnets.
• Achieved low threshold current density (~10 MA cm⁻²) for magnetization switching and high domain wall velocities (up to 300 m s⁻¹).

Conclusions:

• Iridium-based HEAs are effective spin Hall materials for spintronics.
• These HEAs facilitate current-induced magnetization reversal and domain wall motion.
• HEAs show significant potential for high-performance spintronic applications.