Running out of disk space for your movies and music? There's good news from Singapore. Researchers at the Institute of Materials Research and Engineering have found a way to increase the density of hard disk storage by six times over current drives, all thanks to salt.
While he was a graduate student at MIT, IMRE's Dr. Joel Yang developed a new electron-beam lithography process which uses sodium chloride to enhance the developer solution. He and his research team at IMRE, in collaboration with researchers from the National University of Singapore and the Agency for Science, Technology, and Research's Data Storage Institute have refined the process, and have been able to fabricate magnetic storage media with a density of 3.3 terabits per square inch.
Yang's approach is based on bit-patterned recording (BPR), which uses a disk surface with magnetic clusters, or "islands," that prevent the bleeding of data written to one bit of storage to another through supermagnetic effects. The increased density isn't because the process generates smaller magnetic grains on the disk surface. Instead, the sodium chloride allows for more efficient distribution of them through “nanopatterning,” packing grains together in 10-nanometer clusters that form each bit. “What we have shown is that bits can be patterned more densely together by reducing the number of processing steps,” Dr. Yang said in a statement published by IMRE.
The new method also eliminates some of the usual manufacturing processes associated with creating disk platters. In the abstract of the paper Yang and his team published on the results, he wrote, “By avoiding pattern transfer processes such as etching and liftoff that inherently reduce pattern fidelity, the resolution of the final pattern was kept close to that of the lithographic step.”
Perhaps the biggest advantage of Yang's approach is that it uses the same sort of equipment and technology currently used to create disk media. Other efforts to improve magnetic storage density, such as thermally-assisted magnetic recording (also know as heat-assisted magnetic recording, or HAMR) and nano-contact magnetic resistance can in theory generate much higher disk densities, but require new manufacturing equipment and are consequently much more expensive to produce.