Controlling stable Bloch points with electric currents

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Bloch points are critical singularities in magnetization, crucial for understanding magnetic reversal processes.
• Stable Bloch points are essential for developing novel magnetic memory and logic devices.

Purpose of the Study:

• To investigate the controlled manipulation of Bloch points in a two-layer FeGe nanostrip system.
• To explore the collective behavior and pinning dynamics of Bloch points.

Main Methods:

• Utilized spin-transfer torques to drive Bloch point motion in FeGe nanostrips.
• Simulated Bloch point behavior in various geometries, including constrictions and T-shaped structures.

Main Results:

• Demonstrated collective Bloch point movement without Hall effect, with mutual repulsion and boundary avoidance.
• Achieved controlled movement of Bloch point arrays past notches using pulsed currents.
• Showcased path-dependent Bloch point steering in a T-shaped geometry.

Conclusions:

• FeGe nanostrips with opposite chirality provide a stable platform for Bloch point manipulation.
• Spin-transfer torques offer a viable method for controlling Bloch point dynamics and positioning.
• Bloch point behavior can be precisely engineered using geometric confinement and current stimuli.