Towards MnN as a replacement for IrMn.

Area of Science:

• Materials Science
• Solid State Physics
• Spintronics

Background:

• There is a critical need for alternatives to iridium-manganese (IrMn) alloys in antiferromagnetic spintronic devices due to iridium's cost and scarcity.
• Manganese nitride (MnN) on a tantalum (Ta) seed layer has been explored as a potential replacement, but faces challenges with low anisotropy and nitrogen diffusion.

Purpose of the Study:

• To address the limitations of MnN/Ta for high-temperature antiferromagnetic applications.
• To investigate the use of a tungsten (W) seed layer to improve MnN properties and performance.

Main Methods:

• Fabrication of MnN thin films using a W seed layer instead of Ta.
• Characterization of structural properties, including crystallographic texture ({111} growth).
• Measurement of magnetic properties, specifically magnetocrystalline anisotropy.

Main Results:

• Minimized nitrogen diffusion into the W seed layer at elevated temperatures (exceeding 500°C).
• Achieved preferential {111} crystallographic growth of MnN.
• Measured significantly enhanced magnetocrystalline anisotropy ($$), comparable to IrMn.

Conclusions:

• The use of a W seed layer effectively suppresses nitrogen diffusion and enhances the anisotropy of MnN films.
• This approach presents a viable pathway to develop cost-effective, high-performance antiferromagnetic materials for room-temperature and above applications, replacing expensive IrMn alloys.