Today digital data is stored in two main types of devices, magnetic hard disk drives, and solid state random access memories. The former stores data very cheaply but, since it relies on the mechanical rotation of a disk, is slow and somewhat unreliable. The latter allows rapid access to data but the cost is about 100 times higher per bit than a magnetic disk drive.
A new far better alternative is approaching … its called racetrack memory and is based upon spintronics. This is a means of using spin currents to directly manipulate the magnetic state of nano-scale magnetic regions – magnetic domain walls – within magnetic nano-wires. This device, the magnetic race-track, is a powerful storage-class memory which promises a solid state memory with the cost and storage capacities rivaling that of magnetic disk drives but with much improved performance and reliability. If the IBM boffins successfuly crack all the problems, then this could provide another revolution in our ability to access and manipulate digital information.
So what is new?
An article was published in Science on 24th Dec entitled “Dynamics of Magnetic Domain Walls Under Their Own Inertia”, … click here … its abstract reads …
The motion of magnetic domain walls induced by spin-polarized current has considerable potential for use in magnetic memory and logic devices. Key to the success of these devices is the precise positioning of individual domain walls along magnetic nanowires, using current pulses. We show that domain walls move surprisingly long distances of several micrometers and relax over several tens of nanoseconds, under their own inertia, when the current stimulus is removed. We also show that the net distance traveled by the domain wall is exactly proportional to the current pulse length because of the lag derived from its acceleration at the onset of the pulse. Thus, independent of its inertia, a domain wall can be accurately positioned using properly timed current pulses.
The new understanding, revealed in this article, allows the precise control of the placement of these domains, which the IBM team has proven can act as nano-sized data keepers that can not only store at least 100 times more memory than today’s techniques, but can be accessed at much greater speeds. By controlling electrical pulses in the device, the scientists can move these domain walls at speeds of hundreds of miles per hour and then stop them precisely at the position needed — allowing massive amounts of stored information to be accessed in less than a billionth of a second.
Now lets be 100% clear … we have not reached marketplace viability … its just a step along the road, that is fast approaching a tipping point.
“We discovered that domain walls don’t hit peak acceleration as soon as the current is turned on, and that it takes them exactly the same time and distance to hit peak acceleration as it does to decelerate and eventually come to a stop,” said Dr. Stuart Parkin, an IBM Fellow at IBM Research – Almaden. “This was previously undiscovered in part because it was not clear whether the domain walls actually had mass, and how the effects of acceleration and deceleration could exactly compensate one another. Now we know domain walls can be positioned precisely along the racetracks simply by varying the length of the current pulses even though the walls have mass”.
If they finally crack all this, then what will it mean?
In essence … it could enable devices to store much more information — as much as a factor of 100 times greater — while using much less energy than today’s technology.