Just how much data can we cram onto a hard disk? In a paper appearingonline today in Physical Review Letters, EPFL (Ecole PolytechniqueFederale de Lausanne) Professor Harald Brune and his colleagues reportwhat they believe to be the ultimate density limit of magneticrecording.
His group created a self-assembled lattice of non-interactingtwo-atoms-high islands of cobalt on a single-crystal gold substrate.The islands' density -- 26 trillion islands per square inch -- is thehighest yet recorded and 200 times the bit density of current computerhard disks. The magnetic properties of the islands are the most uniformever recorded, and because the islands don't interact with each other,they can each hold one bit of data.
However, it's not a storage medium "ready to use" because theserecords were posted at the uncomfortably cold temperature of -223 C!Above this temperature, thermal excitation starts to reverse themagnetization and the information in the memory gets volatile.
Brune and his colleagues are still trying to solve this blockingtemperature problem using bi-metallic islands of 500-800 atoms that canmaintain the desired magnetic properties at room temperature.
On the web: http://ipn2.epfl.ch/LNS/index.htm.
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