Scientists reveal next generation spintronics to power faster, smaller computers
Tue 6 Oct 2015
A team of physicists are investigating advanced electronic alternative, superconducting spintronics, with the aim of making next generation computers faster and more powerful.
Published in the Nature Physics journal, the researchers outline a study in which they layered a superconductor between a layer of magnetic material and a layer of gold. They found that under certain conditions, charge carriers flowing out of the superconductor magnetised the neighbouring gold.
The scientists argue that the ability to manipulate the magnetism of the currents in this manner will allow for innovative applications in future electronic devices. The project involved collaboration from the University of St Andrews, the University of Bath, the University of Leeds, Royal Holloway and Bedford College (University of London), the ISIS centre and the Paul Scherrer Institute in Switzerland.
Experiment lead Dr Machiel Flokstra, professor at the School of Physics and Astronomy at St Andrews, explained: “Superconductors are materials that, if cooled sufficiently, lose their resistance, that is, they carry electricity without dissipating heat. This is possible because the electrons that carry the electrical charge bind together into pairs that are able to move without losing energy. Each electron is itself like a tiny bar magnet, since these charged electrons spin about their own axes.”
He continued to clarify that when they form into superconducting pairs the electronic ‘spins’ align opposite each other, so the magnetic field balances out. “It transpires that in these new devices these pairs of electrons can be separated into two currents moving in opposite directions, one with magnetic fields (spins) pointing up and one with them pointing down.
“The idea of generating ‘spin currents’ is the basis of the emerging field of spintronics. In conventional electronics only electrical charges can be manipulated, but it is hoped in the field of spintronics that electron spins can also be controlled, leading to novel advanced electronic devices.”
The research has analysed many aspects of spintronics, including the use of a low-temperature scanning probe microscope to study magnetisation reversal of superconducting ‘spin-valve’ samples and disregard alternative origins for remotely-induced magnetisation.
“This is a really ground-breaking piece of research whose long-term goal is to marry the fields of spintronics and superconductivity,” said Professor Simon Bending, Head of the University of Bath’s Department of Physics.
“We believe that for the first time we have observed spin accumulation arising from a current of spin-carrying pairs of superconducting electrons that can be controlled by manipulating the magnetisation direction in a ferromagnetic control electrode,” he added.
“This is the first step to realising superconducting spintronic devices that operate without generating heat and could be the basis for entirely new types of computers that are faster, smaller and more powerful than before.”