Scientists at the University of Cambridge have found evidence that superconductors could be used as an energy efficient source for spin based devices and claim this could revolutionise computing.
Spintronics involves manipulating the angular momentum of an electronic to perform logic operations. However, spin devices require large currents and much of the input energy is wasted as heat. Because superconductors can carry a current without losing energy, they have been seen to provide one potential solution, but scientists have previously believed that superconductors and spintronics were incompatible. The work, conducted at St John's College, shows the natural spin of electrons can be manipulated and, more importantly, detected, within the current flowing from a superconductor. Lead researcher Dr Jason Robinson, said: "If we could combine spintronics with superconductivity, we would be able to take advantage of the benefits that both areas offer to reduce energy wastage. We could create circuits that are highly complex and extremely powerful on the one hand, but very low in terms of their energy demands on the other." While supplying the charge current from a superconductor offers the prospect of zero electrical resistance – and therefore 100% energy efficiency – it is also problematic because of the way in which electron spins behave in superconducting materials. In general, spintronic devices have multiple magnetic and non magnetic layers. In their study, the research team has made superconductivity and spin possible simultaneously by adding an intervening layer of holmium. In short, said the team, a spin bias was created, but superconductivity was retained. Zero resistance in superconductors is derived from 'Cooper Pairs', in which one electron has an 'up' spin and the other 'down'. Dr Niladri Banerjee from the Materials Science Department at the University of Cambridge, said: "What's never been directly demonstrated until now is that Cooper Pairs can serve as transmitters of spin. That's an important step forward since now it is clear that superconductivity can play a key role in spintronics." The next stage of the team's research will be to create a prototype memory element based on superconducting spin currents, and look for new material combinations which would increase the effectiveness of their method. "We've essentially created a marriage that opens up an emerging field called superconducting spintronics," Dr Robinson added. "Much fundamental research is now required in order to understand the science of this new field, but the results offer a glimpse into a future in which supercomputing could be far more energy efficient." Pic: Gruntzooki, via Flickr