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Table Salt Could Allow for 18 Terabyte Hard Drives

Electron Microscopy images of 1.9 and 3.3 Terabit/inch2 densities

Dr Joel Yang at the Institute of Materials Research and Engineering (IMRE) has discovered a way to increase the data density of a drive to 3.3 Terabit/inch2, meaning that it will be possible to manufacture hard drive platters offering 6 TB of storage. Surprisingly the secret ingredient in producing these high-capacity drives is sodium chloride, or rather, your common table salt.

"Conventional hard disks have randomly distributed nanoscopic magnetic grains - with a few tens of grains used to form one bit – that enable the latest hard disk models to hold up to 0.5 Terabit/in2 of information," IMRE explains in a press release. "The IMRE-led team used the bit-patterned media approach, where magnetic islands are patterned in a regular fashion, with each single island able to store one bit of information."

Manufacturers currently use tiny grains of around 7 to 8-nm in size deposited on the surface of storage media. A single bit of data is stored in a cluster of these grains and not in any single grain. However Dr. Yang managed to store the same amount of information on a single grain the size of 10-nm. Thus, replacing several 7-nm grains with one 10-nm grain saves space and allows for denser storage capacities.

In addition to the higher capacity, the IMRE also reveals that the new method can be added to existing lithography processes thanks to a secret ingredient: tablet salt.

"The secret of the research lies in the use of an extremely high-resolution e-beam lithography process that produces super fine nano-sized structures," IMRE reports. "Dr Yang discovered that by adding sodium chloride to a developer solution used in existing lithography processes, he was able to produce highly defined nanostructures down to 4.5-nm half pitch, without the need for expensive equipment upgrades."

Dr. Yang said that the salt-based method has achieved data-storage capability at 1.9 Terabit/in2, though bits of up to 3.3 Terabit/in2 densities were fabricated. Further research and development is aiming to achieve 10 Terabit/inch2 in the future, but don't expect drives using the salt-based process to appear for another two years if not more.