Current-driven dynamics of chiral ferromagnetic domain walls

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Ferromagnetic materials typically lack preferred magnetization rotation direction.
• Broken inversion symmetry in materials can induce chiral spin textures like skyrmions via the Dzyaloshinskii-Moriya interaction (DMI).

Discussion:

• This study investigates ultrathin metallic ferromagnets (Pt/CoFe/MgO and Ta/CoFe/MgO) where DMI stabilizes chiral domain walls (DWs).
• The spin texture of these chiral DWs facilitates exceptionally efficient current-driven motion.
• Spin torque from the spin Hall effect drives DWs in opposite directions, confirming a Néel configuration with left-handed chirality.

Key Insights:

• Chiral domain walls in engineered ferromagnet/heavy metal/oxide heterostructures exhibit highly efficient current-driven motion.
• Direct experimental confirmation of DW chirality and rigidity was achieved through dynamic measurements.
• The findings resolve previous experimental controversies regarding domain wall behavior.

Outlook:

• This work establishes a new avenue for interfacial design in spintronic devices.
• The efficient DW motion demonstrated offers potential for low-power magnetic memory and logic applications.
• Further exploration of DMI-engineered chiral textures could unlock novel spintronic functionalities.