Graphene breakthrough promises ‘million-fold improvement’ in current hard drive storage capacity
Mon 16 Mar 2015
Research scientists at the U.S. Naval Research Laboratory have developed a technique of magnetising graphene that it claims promises a ‘million-fold’ increase in the current storage capability of hard drives.
Graphene can exhibit magnetic properties either through manufacturing defects or the binding of chemical groups to the so-called ‘wonder’ material, but the problem of creating large-area magnetic graphene has proved elusive. The NRL claims to have solved the problem with ‘simple and robust’ means by placing graphene on a silicon wafer and then submerging it for a minute in cryogenic ammonia and lithium. The process causes the surface to become reliably electromagnetic via the regulated addition of hydrogen atoms.
The photo on the right shows a magnetic force microscopy image of part of a large array created by NRL scientists, depicting a map of the magnetic strength of the hydrogenated ferromagnetic graphene filigree together with the 500nm-wide non-magnetised graphene squares.
Dr. Keith Whitener of the Naval Research Laboratory’s Chemistry Division points out that length of exposure during the process is critical. “This method of hydrogenation gives us access to a much wider range of hydrogen coverage than previous methods allowed,” he says, “and too much hydrogen actually destroys the magnetism,”
However the report notes that with the spectrum process respected, the resultant magnetised graphene is of ‘exceptional quality’. Whitener’s colleague Dr. Paul Sheehan noted “I was surprised that the partially hydrogenated graphene prepared by our method was so uniform in its magnetism and apparently didn’t have any magnetic grain boundaries,”
The research developed a process whereby the magnetic strength of the transformed graphene could be adjusted by using an electron beam to crop away hydrogen atoms, which permits magnetic patterns – data – to be written onto the magnetised material.
Dr. Woo-Kyung Lee is a materials research scientist at the Chemistry Division at the Naval Research Laboratory, and says: “Since massive patterning with commercial electron beam lithography system is possible, we believe that our technique can be readily applicable for current microelectronics fabrication,”
The NRL’s research promises “a storage medium with a single hydrogenated-carbon pair storing a single magnetic bit of data”, according to the report, “a roughly greater than million-fold improvement over current hard drives,”