A more reliable way to grow magnetic nanoparticles could help create the densest form of computer memory yet. The new technique, developed by researchers at North Carolina State University, makes it possible to arrange magnetic "nanodots"--particles around six nanometers wide--in orderly arrays, making it easier to use them to store bits of information magnetically.

Jay Narayan, a professor of material science at North Carolina State University who led the work, says that a nanodot chip measuring one centimeter square could, in theory, store a terabit of data--50 times more than flash, the densest form of memory currently available.

Narayan's group measured the magnetic properties of individual nanodots to show that they could hold magnetic information reliably. Talks are under way with memory manufacturers including Hitachi and Seagate to commercialize the technology, he says.

"The primary innovation is that we can keep all these dots ordered and aligned in the same way," says Narayan. This applies not just to their physical alignment but also their magnetic orientation, which is crucial for switching their magnet states and reading them, he says.

Other researchers have created nanodots similar in size to Narayan's. Mark Welland, head of Cambridge University's Nanoscale Science Laboratory in the U.K., leads a group that has developed nanodots in hexagonal arrays. The trouble for Welland's group is that the magnetic orientation of a nanodot is determined by its physical orientation; since the arrays were hexagonal, their magnetic fields were not all pointing in the same direction.