'Spintronics' brings IBM's Racetrack Memory closer to reality
'New physics' of electrons that only move in one direction
The Manager of IBM's Magnetoelectronics Almaden Research Center says ideas discussed at a Sydney conference on “Spintronics” will help to advance Big Blue's vision for “Racetrack Memory”, a technology that we've previously explained “involves sending magnetic "stripes" through nanowires, written by imparting spin to the electrons and read by an analog to a hard drive's read head.”
The Manager in question is Dr Stuart Parkin, who this week attended an event called WUN-SPIN 2012 hosted by the WUN Spintronics Consortium at the University of Sydney. Parkin, an IBM fellow whose work has contributed greatly to storage media density, demonstrated Racetrack Memory in 2008. The technology relies on a phenomenon called “electron spin” that makes it possible to assemble materials with consistent qualities by controlling electrons' angular momentum. If spin can be read it can be interpreted as representing binary data.
But designing and manufacturing materials that can use spin in more sophisticated ways, as required by ideas like Racetrack Memory, isn't easy.
“The big question is how to design a system that lets you input and read spin,” Professor Simon Ringer, Director of the Australian Centre for Microscopy and Microanalysis and an organiser of WUN-SPIN 2012, told The Reg. Electrical current alone won't suffice, while magnetic fields create their own problems. Using different materials as intermediary layers or “doping” substances to improve their performance as spin carriers is one approach, but Professor Ringer said no single discipline will deliver fine spin control.
The umbrella term for the various efforts needed to control spin are now called "Spintronics", and Professor Ringer said it is "a multi-disciplinary field involving materials science and engineering, and to eventually harness both charge and spin in real devices, we have a lot of fundamental materials science to work through."
"We need theoreticians, fabricators and microscopists all working closely together to sort out the new physics and head the science towards some of the exciting technological drivers. And we are already seeing huddles where collaborations and new ideas are starting to blossom."
Ringer's own field, microscopy, contributes by allowing scientists to observe events at the atomic level, the better to understand how spin-carrying electrons behave.
And that behaviour is of considerable interest, because the new physics Ringer mentioned involve the behaviour of electrons set to a particular spin. It turns out that electrons spinning in certain will only move in one direction – either left or right - behaviour Dr Parkin declared “an amazing discovery.”
Just what will become possible when boffins figure out how to harness electrons that behave this way isn't known, but Parkin told The Reg he feels that some the ideas he heard at the conference will advance development of Racetrack Memory. There's still no likely release date for the memory, but Parkin sounded urgent: he predicted DRAM has just five years more of advances before the technologies underpinning it hit fundamental physical barriers that prevent further enhancement. ®