The big hoopla as of late has been wrapped around SSD’s and flash memory technology, with constant die shrinks promising cheaper and faster solid state storage for your PC. Everyone seems to be slowly forgetting about good old HDD’s, but spinning rust may have some life left after all.
A team of scientists formed iron and gadolinium into a series of alloy ‘nanoislands’. These are basically isolated mini magnets. Each one carries a magnetic charge. Normally you would write to materials like this by hitting them with a much larger magnetic field (i.e. from your HDD write head). This team had a different trick up their sleeve – don’t bother with the bigger magnet, just hit it with a burst of heat and get it to change state on its own.
Magnetic nanoislands getting hit by a frickin’ laser.
Picture a sling shot, stretched out, and frozen in a block of ice. If you melt the ice, the rubber band will just snap back to its unstretched state and stay there. The same kind of thing happens when you heat a magnet – it becomes demagnetized. Now imagine if you could melt the ice, but flash freeze it while the rubber band has extended in the opposite direction. You’ve reversed the direction of the sling shot. Pull off the same trick with a magnet, and you can flip its poles. The trick is finding just the right length of time to heat the magnet and catch the ‘flip’ on the other end of its resonance. This team appears to have figured it out, and the magic number (for their material) is 60 femtoseconds. They can heep hitting the same spot repeatedly, and each time causes another flip in the poles.
Each pulse flips the bit.
To back this down into typical computer terms. A 1GHz CPU clock triggers every 1.00000 nanosecond, and 60 femtoseconds is 0.00006 nanoseconds. Ultrashort Pulse lasers have been around for a while. One was even used on my eyeballs a few years back. These pulses are so fast that the biggest issue would be getting information to the laser fast enough. The straight line theoretical speed of this technique ranges in the Terabytes per second, with densities limited by the capabilities of the nanotech used to create the islands.
To be clear, this isn’t the first time heat or lasers has been used in magnetic media. TDK pioneered Heat Assisted Magnetic Recording tech years ago, but that tech is only heat *assisted*. This new breakthrough is writing, with heat, without the magnet at all. Now the only trick is figuring out how to read such a high density of tiny written bits. Since the laser writes much smaller than a magnetic head could accomplish, we might see a reversion back to optics for the reads.We’re not sure how long before this technology appears on your desktop, but what we can say is that magnetic storage is not dead yet.