Perpendicular magnetic tunnel junction with a strained Mn-based nanolayer.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Spintronics

Background:

• Perpendicular magnetic tunnel junctions (p-MTJs) are crucial for spintronic non-volatile magnetoresistive random access memory (MRAM).
• Current Co-Fe-B based p-MTJs face limitations due to high magnetization and moderate perpendicular magnetic anisotropy (PMA), hindering dense MRAM applications.

Purpose of the Study:

• To develop a p-MTJ with properties suitable for advanced MRAM.
• To overcome the limitations of existing Co-Fe-B based p-MTJs.

Main Methods:

• Fabrication of a p-MTJ utilizing an epitaxially strained MnGa nanolayer.
• Growth of the MnGa layer on a novel CoGa buffer material.
• Experimental characterization of magnetic properties and tunnel magnetoresistance (TMR).
• First-principles calculations to investigate electronic structure and spin polarization.

Main Results:

• Demonstrated a p-MTJ with a large PMA (>5 Merg/cm³) and low magnetization (<500 emu/cm³).
• Achieved properties suitable for advanced MRAM applications.
• First-principles calculations predicted a potential for a huge TMR effect due to strain-induced band structure modification and full spin polarization.

Conclusions:

• The developed MnGa/CoGa based p-MTJ shows promise for next-generation MRAM.
• Strain engineering in the MnGa nanolayer is key to achieving desirable magnetic properties.
• Further optimization is needed to enhance the experimental TMR ratio, but theoretical predictions indicate significant potential.