Improving Néel Domain Walls Dynamics and Skyrmion Stability Using He Ion Irradiation.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Spintronics

Background:

• Perpendicular magnetic anisotropy (PMA) is crucial for magnetic storage technologies.
• Tuning magnetic properties of thin films is essential for advanced spintronic devices.
• Interfacial Dzyaloshinskii-Moriya interaction (DMI) plays a key role in domain wall motion.

Purpose of the Study:

• Investigate the impact of Helium ion (He+) irradiation on PMA and domain wall dynamics in Pt/Co/AlOx trilayers.
• Determine the effect of He+ irradiation on spontaneous magnetization and interfacial DMI.
• Explore the potential for decoupling PMA from DMI to enhance device performance.

Main Methods:

• Irradiation of Pt/Co/AlOx thin films with He+ ions at various fluences.
• Characterization of magnetic properties, including PMA, spontaneous magnetization, and DMI.
• Analysis of domain wall dynamics and depinning fields.
• Observation of magnetic skyrmions and their behavior under irradiation.

Main Results:

• He+ irradiation significantly decreases PMA without affecting spontaneous magnetization or DMI strength.
• Experimental confirmation of DMI robustness against interfacial intermixing.
• Reduced domain wall depinning field observed after irradiation, enabling higher domain wall velocities.
• Stabilization of magnetic skyrmions, with decreasing size and increased stability at higher He+ fluences.

Conclusions:

• Decoupling PMA from DMI via He+ irradiation offers a pathway for designing energy-efficient spintronic devices.
• The observed control over PMA and domain wall dynamics is beneficial for applications leveraging domain wall motion.
• He+ irradiation provides a method to tune magnetic properties and stabilize magnetic textures like skyrmions.