Large Spin-Orbit Torque in a-Plane α-Fe_{2}O_{3}/Pt Bilayers

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Efficient switching of the Néel vector in insulating antiferromagnets is crucial for spintronics but challenging due to spurious effects.
• Quantifying spin-orbit torques (SOT) in heterostructures is a key step towards realizing this goal.

Purpose of the Study:

• To quantify dampinglike spin-orbit torque (DL-SOT) in a-plane α-Fe_{2}O_{3} (hematite) using a platinum (Pt) overlayer.
• To investigate the potential of a-plane hematite for efficient SOT switching applications.

Main Methods:

• Magneto-optic techniques were employed to study DL-SOT.
• Harmonic Hall techniques were used for comparison with previous studies.
• Direct imaging of current-induced antiferromagnetic domain motion was performed.

Main Results:

• DL-SOT efficiency in a-plane hematite/Pt was found to be two orders of magnitude greater than in other hematite orientations.
• Current-induced motion of antiferromagnetic domains was observed at moderate current densities.
• A new method for quantifying SOT in antiferromagnets with small canted moments was introduced.

Conclusions:

• A-plane α-Fe_{2}O_{3} exhibits significantly enhanced DL-SOT efficiency.
• This material is a promising candidate for realizing efficient SOT switching in antiferromagnets.
• The findings pave the way for advanced spintronic devices.