Shape anisotropy revisited in single-digit nanometer magnetic tunnel junctions

Area of Science:

• Spintronics
• Materials Science
• Nanotechnology

Background:

• Magnetic tunnel junctions (MTJs) are crucial for magnetoresistive random-access memories (MRAM).
• Achieving low switching currents and high thermal stability simultaneously is essential for reducing MTJ size.
• Current perpendicular MTJs using CoFeB/MgO stacks are limited to ~20 nm.

Purpose of the Study:

• To explore a new approach for fabricating MTJs at ultrafine scales (<10 nm).
• To investigate the role of shape anisotropy in achieving desired MTJ properties.
• To enable magnetization switching solely by current in sub-10 nm MTJs.

Main Methods:

• Revisiting and utilizing shape anisotropy in MTJ design.
• Fabricating MTJs at the nanoscale, focusing on dimensions below 10 nm.
• Experimental characterization of magnetization switching and thermal stability.

Main Results:

• Demonstrated current-driven magnetization switching in MTJs smaller than 10 nm.
• Shape anisotropy provided sufficient thermal stability without new materials.
• Successfully satisfied requirements for ultrafine-scale MTJs.

Conclusions:

• Shape anisotropy is a viable strategy for advancing MTJ technology to single-digit nanometer scales.
• This approach can overcome limitations of current perpendicular MTJ systems.
• The findings are expected to accelerate the development of nano-magnetics and spintronics devices.