# Graphene Overcoats for Ultra-High Storage Density Magnetic Media

## TL;DR

This paper demonstrates that graphene overcoats significantly improve the durability and performance of magnetic storage media, enabling higher data densities and compatibility with heat-assisted recording technologies.

## Contribution

The study introduces graphene-based overcoats as a superior alternative to traditional carbon overcoats, achieving enhanced friction, corrosion, wear resistance, and thermal stability at sub-2nm thickness.

## Key findings

- Graphene overcoats double the reduction in friction compared to current coatings.
- A single graphene layer reduces corrosion by approximately 2.5 times.
- Graphene withstands heat-assisted magnetic recording conditions.

## Abstract

Hard disk drives (HDDs) are used as secondary storage in a number of digital electronic devices owing to low cost ($<$0.1\$/GB at 2016 prices) and large data storage capacity (10TB with a 3.5 inch HDD). Due to the exponentially increasing amount of data, there is a need to increase areal storage densities beyond$\sim$1Tb/in$^2$. This requires the thickness of carbon overcoats (COCs) to be$<$2nm. Friction, wear, corrosion, and thermal stability are critical concerns$<$2nm, where most of the protective properties of current COCs are lost. This limits current technology and restricts COC integration with heat assisted magnetic recording technology (HAMR), since this also requires laser irradiation stability. Here we show that graphene-based overcoats can overcome all these limitations. 2-4 layers of graphene enable two-fold reduction in friction and provide better corrosion and wear than state-of-the-art COCs. A single graphene layer is enough to reduce corrosion$\sim$2.5 times. We also show that graphene can withstand HAMR conditions. Thus, graphene-based overcoats can enable ultrahigh areal density HDDs$>$10Tb/in$^2$.