Cambridge University’s Graphene Center has infused ultra-high density hard disk drives (HDDs) with graphene, resulting in a tenfold increase in data storing capacity.
HDDs – which first appeared in the 1950s – contain two major components: platters and a head. Data are written on the platters using a magnetic head, which moves rapidly above them as they spin. The space between head and platter is continually decreasing to enable higher densities.
As of today, platters are protected from mechanical damages and corrosion by layers of carbon-based overcoats (COCs) and these occupy a significant part of the head-platter spacing.
The COC thickness which once stood at 12.5nm has now been reduced to 3nm, corresponding to one terabyte per square inch.
The Cambridge team and scientists from the University of Exeter, India, Switzerland, Singapore, and the US. – have now shown how one could increase that spacing and storage capacity with the help of graphene
The scientists first replaced commercial COCs with one to four layers of graphene, and tested friction, wear, corrosion, thermal stability, and lubricant compatibility.
Beyond its unbeatable thinness, graphene fulfilled all the ideal properties of an HDD overcoat in terms of corrosion protection, low friction, wear resistance, hardness, lubricant compatibility, and surface smoothness.
It moreover enabled a two-fold reduction in friction and provided better corrosion and wear than state-of-the-art solutions. In fact, one single graphene layer was able to reduce corrosion by 2.5 times.
The Cambridge team then transferred graphene onto hard disks made of iron-platinum as the magnetic recording layer, and tested Heat-Assisted Magnetic Recording (HAMR) – a new technology that enables an increase in storage density by heating the recording layer to high temperatures.
Current COCs do not perform at these high temperatures, but graphene does. Thus, graphene, coupled with HAMR, can outperform current HDDs, providing an unprecedented data density, higher than 10 terabytes per square inch.
Image and content: bohed-Pixabay/University of Cambridge