|Hard drives store data on discs coated with a metallic film divided into
tiny magnetic regions, each of which stores a single bit - the more
regions you can squeeze on to a disc, the bigger the capacity. Now, a
team at the University of Leeds, UK, have borrowed a trick from nature
to build a new kind of hard drive.
Certain strains of bacteria absorb iron to make magnetic nanoparticles
that let them navigate using the Earth's magnetic field. The team have
extracted the protein behind this process and used it to create magnetic
patterns that can store data.
Hard drives are usually made by 'sputtering', in which clouds of argon
ions are fired at a sheet of magnetic material, knocking off particles
which are deposited as a thin film on a disc. Groups of these particles,
called grains, form the magnetic regions on the drive, with around 100
grains corresponding to one bit.
Instead of granular media, the Leeds team produce bit-patterned media.
They start with a gold surface coated in chemicals in a chessboard
pattern so that one set of squares binds proteins and the other repels
them. They then apply the magnet-producing protein and coat the surface
with an iron solution, which the protein-covered squares convert into
Each magnetic square in bit-patterned media can store one bit. Each
square the team have so far produced is around 20 micrometres wide, far
too bulky to store data with a density comparable to today's hard
drives. They now plan to test out nano-sized squares, much closer to
existing drive density. Eventually, they hope to create a disk with a
single iron particle per square, which will store as much as 1 terabyte
of data per square inch - far beyond the capability of most hard drives.