1,000 times faster than current hard drives
Hold onto your hats: An international team of scientists working in England, Russia, Switzerland, and the Netherlands have completely rewritten the rules of magnetic storage. Instead of switching a magnetic region using a magnetic field (like a hard drive head), the researchers have managed to switch a ferrimagnetic nanoisland usinglasers. Storing magnetic data using lasers is up to 1,000 times faster than writing to a conventional hard drive.
To achieve this, the researchers created ferrimagnetic nanoislands (pictured above) out of an alloy of iron and gadolinium (a rare earth metal). When these nanoislands are struck by a 60-femtosecond laser (0.06 picoseconds, or 0.00006 nanoseconds) their magnetism switches (pictured below). If you know a little about the science of magnetism, you’ll know that this behavior is rather funky as we usually associate heat with destroying magnetism, rather than switching it.
In total, it takes a nanoisland five picoseconds to switch state (from binary 0 to binary 1). By comparison, it takes about one nanosecond to switch the value of a magnetic region on a hard drive platter. In other words, we are looking at a storage technique that’s about 1,000 times faster than current hard drives. Instead of storing hundreds of megabytes per second, the use of femtosecond lasers would enable the transfer of gigabytes or terabytes per second.
That’s not all! Current hard drive platters have a density of around three terabits per square inch, but nanoislands are so small that you could cram in 53 terabits per square inch. Instead of a terabyte per platter, we would be looking at 15 terabytes per platter and 45TB hard drives. Apparently femtosecond lasers are more efficient than spinning a hard drive head around at thousands of RPM, too, though the researchers don’t give any hard figures.
Finally, though, it’s worth noting that the scientists only discuss how to write data, not read. Ferrimagnets, like antiferromagnets, don’t generally have a magnetic field. In other words, York’s nanoisland storage medium can’t simply replace a hard drive platter. At the moment, data is probably read using a scanning tunneling electron microscope — and for the time being, they’re still very much room-sized devices
