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Some superconductors can also carry currents of ‘spin’

last modified Apr 17, 2018 05:18 PM

Researchers have shown that certain superconductors, materials that carry electrical current with zero resistance at very low temperatures, can also carry currents of ‘spin’. The successful combination of superconductivity and spin could lead to a revolution in high-performance computing, by dramatically reducing energy consumption. 

Spin is a particle’s intrinsic angular momentum, and is normally carried in non-superconducting, non-magnetic materials by individual electrons. Spin can be ‘up’ or ‘down’, and for any given material, there is a maximum length that spin can be carried. In a conventional superconductor electrons with opposite spins are paired together so that a flow of electrons carries zero spin.

A few years ago, researchers from the University of Cambridge showed that it was possible to create electron pairs in which the spins are aligned: up-up or down-down. The spin current can be carried by up-up and down-down pairs moving in opposite directions with a net charge current of zero. The ability to create such a pure spin supercurrent is an important step towards the team’s vision of creating a superconducting computing technology which could use massively less energy than the present silicon-based electronics.

University of Cambridge researchers have shown that it was possible to create electron pairs in which the spins are aligned: up-up or down-down. The spin current can be carried by up-up and down-down pairs moving in opposite directions with a net charge current of zero. The ability to create such a pure spin supercurrent is an important step towards the team’s vision of creating a superconducting computing technology which could use massively less energy than the present silicon-based electronics.

The same researchers have now found a set of materials which encourage the pairing of spin-aligned electrons, so that a spin current flows more effectively in the superconducting state than in the non-superconducting (normal) state. “Although some aspects of normal state spin electronics, or spintronics, are more efficient than standard semiconductor electronics, their large-scale application has been prevented because the large charge currents required to generate spin currents waste too much energy,” said Professor Mark Blamire, Department of Materials Science and Metallurgy, who led the research.

 

Click here for the full University of Cambridge research Article.

Click here for the Nature Materials publication.

 

Image credit: Dr Jason Robinson