Observation of Spin-Splitter Torque in Collinear Antiferromagnetic RuO_{2}

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• The spin-splitter effect theoretically predicts unconventional spin currents in antiferromagnets.
• This effect can generate spin-splitter torque for manipulating magnetization without external magnetic fields, crucial for spintronic devices like MRAM.

Purpose of the Study:

• To investigate the generation of spin-splitter torque in collinear antiferromagnetic RuO2.
• To analyze spin current polarization across different RuO2 crystal planes and Néel vector orientations.
• To demonstrate the practical application of spin-splitter torque for field-free magnetization switching.

Main Methods:

• Theoretical study of spin current generation in RuO2 with (100), (101), and (001) crystal planes.
• Analysis of spin polarization (x, y, z) based on Néel vector direction.
• Experimental demonstration of field-free switching using z-polarized spin currents at room temperature.

Main Results:

• RuO2(101) exhibits x-, y-, and z-polarized spin currents dependent on the Néel vector.
• RuO2(100) and (001) primarily show a Néel vector-independent y-polarized spin current.
• Successful field-free switching of perpendicular magnetized ferromagnets was achieved using z-polarized spin currents from RuO2.

Conclusions:

• The spin-splitter torque generated by RuO2 is effective for magnetization switching.
• This research validates the utility of the spin-splitter effect in antiferromagnetic spintronics.
• Findings contribute to understanding the spin-splitter mechanism and advancing antiferromagnetic spin-orbitronics.