Enhanced interfacial Dzyaloshinskii-Moriya interactions in annealed Pt/Co/MgO structures

Area of Science:

• Spintronics
• Materials Science
• Condensed Matter Physics

Background:

• The interfacial Dzyaloshinskii-Moriya interaction (iDMI) is critical for spintronic applications.
• Achieving iDMI constants greater than 3 mJ m^-2 is essential for minimizing skyrmion size and enhancing domain-wall dynamics.

Purpose of the Study:

• To experimentally demonstrate and enhance giant iDMI in ultra-thin film structures.
• To investigate the role of inserted materials (Ta, Mg) and thermal annealing on iDMI.
• To understand the underlying physics of iDMI enhancement using ab-initio calculations.

Main Methods:

• Fabrication of Pt/Co/X/MgO ultra-thin films with perpendicular magnetization.
• Measurement of iDMI constants using a field-driven creep regime domain expansion method.
• Ab-initio calculations to understand iDMI enhancement mechanisms.
• Thermal annealing to crystallize MgO and improve tunneling magnetoresistance (TMR).

Main Results:

• Demonstration of a giant iDMI in Pt/Co/X/MgO structures.
• Significant enhancement of iDMI observed with atomically thin insertions of Ta and Mg.
• Further increase in iDMI constant up to 3.3 mJ m^-2 after thermal annealing.
• Correlation between MgO crystallization, improved TMR, and increased iDMI.

Conclusions:

• The study successfully achieved and enhanced giant iDMI in a promising material system.
• Atomic-scale engineering and post-processing (thermal annealing) are effective strategies for boosting iDMI.
• The achieved iDMI values are highly promising for the development of next-generation skyrmion-based spintronic devices.