Skyrmion Dynamics in a Double-Disk Geometry under an Electric Current.

Area of Science:

• Spintronics
• Condensed Matter Physics
• Materials Science

Background:

• Skyrmions are topologically protected spin textures with potential for data storage and logic devices.
• Understanding skyrmion dynamics is crucial for developing practical spintronic devices.
• Dzyaloshinskii-Moriya interactions play a key role in stabilizing and manipulating skyrmions.

Purpose of the Study:

• To investigate skyrmion dynamics in a double-disk spintronic toroidal oscillator (STNO) geometry.
• To analyze the influence of geometric parameters and electric current density on skyrmion behavior.
• To identify and characterize different skyrmion dynamic regimes.

Main Methods:

• Numerical simulations were employed to model skyrmion behavior.
• The analysis considered Dzyaloshinskii-Moriya interactions within the STNO device.
• Three distinct skyrmion dynamic regimes were observed and analyzed.

Main Results:

• Identified three regimes: skyrmion annihilation at the border, non-circular motion between disks, and rotation within a single disk.
• Observed that transient time for annihilation follows a stretched exponential decay with electric current.
• Developed a 2D state diagram illustrating these behaviors as a function of geometric parameters and current density.

Conclusions:

• The study provides a comprehensive analysis of skyrmion dynamics in a specific STNO geometry.
• The findings offer insights into controlling skyrmion motion for potential applications.
• The generated state diagram serves as a guide for experimental realization of desired skyrmion behaviors.