Breaking the 2-nm Barrier in Hard Disk Drives Using Monolayer Amorphous Carbon Overcoats

Area of Science:

• Materials Science
• Data Storage Technology

Background:

• Artificial intelligence (AI) drives demand for large-scale data storage, making hard disk drives (HDDs) crucial for data centers.
• Increasing areal storage density in HDDs is vital for AI, but is limited by traditional carbon overcoats (COCs).
• Next-generation technologies like Heat-Assisted Magnetic Recording (HAMR) require ultrathin, thermally stable protective layers beyond current diamond-like carbon (DLC) capabilities.

Purpose of the Study:

• To introduce and evaluate monolayer amorphous carbon (MAC) as a novel protective layer for HDD media.
• To assess MAC's suitability for next-generation HDDs, particularly for achieving ultra-high areal storage densities.
• To demonstrate MAC's performance under conditions relevant to advanced magnetic recording technologies.

Main Methods:

• Directly growing monolayer amorphous carbon (MAC) on heterogeneous HDD surfaces (Fe, Pt, SiO2) at low temperatures (~300°C).
• Characterizing MAC's thickness uniformity (0.8 nm), corrosion resistance, surface roughness, and thermal stability (~450°C).
• Evaluating MAC's friction coefficient and potential for lubricant-free operation.

Main Results:

• Achieved uniform 0.8 nm MAC coatings on 2.5-inch disks.
• MAC exhibited high corrosion resistance and low roughness, comparable to 2.5 nm commercial COCs.
• Demonstrated excellent thermal stability under HAMR-like conditions and a low friction coefficient.

Conclusions:

• Monolayer amorphous carbon (MAC) is a superior alternative to traditional carbon overcoats (COCs) for advanced HDDs.
• MAC enables the development of HDD media capable of reaching 10 Tb/in², meeting the demands of the digital era.
• The properties of MAC facilitate the advancement of data storage technologies, supporting AI-driven data requirements.