Enhanced thermally-activated skyrmion diffusion with tunable effective gyrotropic force.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Magnetic skyrmions are topologically-stabilized spin textures with unique electromagnetic properties.
• The topology of skyrmions generates a gyrotropic force, influencing their deterministic motion (e.g., skyrmion Hall effect).
• The impact of gyrotropic force on stochastic diffusive motion of skyrmions remains largely unexplored.

Purpose of the Study:

• To demonstrate the influence of gyrotropic force on the diffusive motion of magnetic skyrmions.
• To investigate enhanced thermally-activated diffusive motion in specifically designed synthetic antiferromagnets.
• To explore the potential for energy-efficient unconventional stochastic computing.

Main Methods:

• Designed and fabricated a synthetic antiferromagnet system to precisely tune skyrmion properties.
• Investigated skyrmion dynamics by manipulating angular momentum compensation to suppress the effective gyrotropic force.
• Quantified the diffusion coefficient of skyrmions and compared it to ferromagnetic systems.

Main Results:

• Demonstrated significantly enhanced thermally-activated diffusive motion of skyrmions.
• Achieved over a 10-fold increase in the diffusion coefficient compared to ferromagnetic skyrmions.
• Established a clear dependence of the diffusion coefficient on the gyrotropic force.

Conclusions:

• The gyrotropic force plays a crucial role in the stochastic diffusive motion of magnetic skyrmions.
• Suppressing the gyrotropic force in synthetic antiferromagnets leads to dramatically enhanced diffusion.
• These findings pave the way for developing highly energy-efficient unconventional stochastic computing devices.