Optimizing Perpendicular Magnetic Anisotropy in MgO/CoFeB Structures Through Ultrathin CoFeB-Enhanced Ta Capping...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Perpendicular magnetic anisotropy (PMA) is critical for high-density magnetic storage devices.
• Optimizing the CoFeB/MgO interface is key to enhancing PMA performance and thermal stability.
• Interfacial diffusion and oxidation control are significant challenges in fabricating robust magnetic heterostructures.

Purpose of the Study:

• To investigate the effect of an ultrathin CoFeB insertion layer on PMA in CoFeB/MgO structures.
• To enhance the interfacial magnetic anisotropy and thermal stability of CoFeB/MgO stacks.
• To provide a scalable method for improving PMA compatible with semiconductor manufacturing.

Main Methods:

• Fabrication of CoFeB/MgO stacks with a strategic ultrathin CoFeB insertion layer (0.43 nm) between the CoFeB/MgO and the top capping layer (Ta or Mo).
• Postannealing treatment at 400 °C to optimize interfacial properties.
• Characterization using high-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS) to analyze structural and chemical properties.

Main Results:

• The insertion of a 0.43 nm CoFeB layer significantly boosted PMA, achieving an interfacial anisotropy constant (K) of 3.8 erg/cm².
• The CoFeB insertion layer effectively suppressed interfacial diffusion from the Ta or Mo capping layer.
• Improved Fe-O hybridization and stabilized MgO crystallinity were observed, leading to enhanced interfacial integrity.

Conclusions:

• The ultrathin CoFeB insertion layer is a highly effective strategy for enhancing PMA and thermal stability in CoFeB/MgO structures.
• This approach offers a promising solution for next-generation spintronic devices, compatible with CMOS back-end-of-line processing.
• Interfacial engineering through strategic layer insertion is crucial for advancing spintronic technology performance.