Hard drives have resisted all projections, and despite the spectacular advance of solid-state drives, the classic magnetic-mechanical storage medium has never stopped growing. At the same time, several top-tier companies are looking to push that technology to the extreme. Last July, the University of Delft managed to store a bit per atom, and now it is the turn of IBM Research, which has achieved that same mark with a new atomic hard drive based on holmium.
Competition in the hard drive market remains very healthy. Last December, Western Digital announced new 12 and 14 terabyte drives, but earlier this year Seagate confirmed it would need only eighteen months to reach 16 terabytes. In some way, manufacturers keep increasing the capacity of their drives without sacrificing the current form factor, a detail that servers, data centers, and independent users around the world truly appreciate. That said, what is the limit? Recently we talked about the potential of DNA as a storage medium, but the question is aimed at magnetic technology. According to IBM Research, the answer is one atom.
The story dates back to January 2012, when IBM needed just twelve atoms to store a bit. Back then, the company used iron atoms on a copper substrate at a temperature of one degree Kelvin, but this time it is a single holmium atom on a magnesium oxide surface. Technically, IBM Research presented this work as "the smallest magnet in the world", and by changing the magnetic direction of the atom, it established a mechanism of "0" and "1", allowing a bit to be read and written. In other words, the IBM Research magnet is also an atomic hard drive.
If we consider that a typical hard drive needs about one hundred thousand atoms to store a single bit, it is not hard to visualize the drastic improvement in density. In theory, the entire iTunes catalog could be stored on a device as large as a credit card, with space to spare. Now, we have our doubts about a possible direct application of this development in the real world. The read/write process requires a scanning tunneling microscope cooled with liquid nitrogen. Maybe it will give way to much denser and more compact drives, but we imagine the "bit per atom" will never leave the laboratory...
