Experimental Evidence of Curvature Gradient Driven Domain Wall Automotion

Area of Science:

• Nanomagnetism
• Spintronics
• Fundamental Physics

Background:

• Geometrical effects in nanomagnetism have significant implications for applications like domain wall (DW) motion.
• Experimental validation of geometry-induced effects on DW motion is crucial but remains limited.

Purpose of the Study:

• To experimentally demonstrate that curvature gradients dictate domain wall motion in magnetic nanostructures.
• To explore the potential of curvature engineering for low-energy spintronic devices.

Main Methods:

• Utilizing spiral-shaped magnetic nanostructures subjected to a saturating magnetic field.
• Inducing magnetic onion states to generate head-to-head (HtH) and tail-to-tail (TtT) DWs.
• Measuring depinning fields, supported by micromagnetic simulations and an analytical model.

Main Results:

• Curvature gradients were shown to promote DW motion towards regions of higher curvature.
• A local curvature-dependent effective force was identified as the driving mechanism.
• Experimental findings were corroborated by micromagnetic simulations and an analytical model.

Conclusions:

• Curvature gradients are a key factor in controlling domain wall motion in nanomagnetic systems.
• Curvature engineering presents a promising pathway for the development of energy-efficient spintronic devices.