Magnetic memory driven by spin splitting torque in nonrelativistic collinear antiferromagnet

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Magnetic random-access memory (MRAM) is a leading next-generation memory technology due to its energy efficiency and speed.
• Spin splitting band structures in antiferromagnets offer novel methods for controlling spin currents.
• Altermagnetism presents unique opportunities for spintronic device functionalities.

Purpose of the Study:

• To demonstrate field-free switching in a magnetic tunnel junction (MTJ) using altermagnetic spin splitting torque (SST).
• To integrate an altermagnetic (101)-RuO2 writing channel with an MTJ for a 3-terminal device.
• To explore the potential of altermagnetic SST-MRAM for advanced memory applications.

Main Methods:

• Integration of a (101)-RuO2 altermagnetic writing channel with a perpendicular-MTJ.
• Utilizing altermagnetic spin splitting torque (SST) for device switching.
• Characterization using magneto-optic Kerr effect (MOKE) microscopy and magnetic hysteresis loop measurements.

Main Results:

• Successful demonstration of all-electrical, field-free switching of the perpendicular-MTJ via altermagnetic SST.
• Observation of tilted spin polarization and transversal spin current flow.
• Direct visualization of field-free altermagnetic SST-driven magnetic domain switching using MOKE.

Conclusions:

• The research provides a foundation for developing altermagnetic SST-MRAM.
• This technology paves the way for all-electrical, energy-efficient, and high-endurance MRAM.
• Separated writing and reading channels are achievable with altermagnetic devices.