By Josh Perry, Editor
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Scientists at the University of Konstanz (Germany) have demonstrated that lossless electrical transfer (superconductivity) of magnetically encoded information is possible, which could enhance storage density on integrated circuits (IC) and reduce energy consumption of computing centers.

Scanning Tunnelling Microscope installed in a helium cooling device seen from below (with the sample stage removed). (Simon Diesch/University of Konstanz)

According to a report from the university, this breakthrough advances the study of spintronics, which could use the spin of electrons to transport data without producing heat.

Previously, scientists understood superconductors as carrying current through pairs of electrons with opposite magnetic moments.  “Recent findings suggest that by bringing superconductors into contact with special magnetic materials, electrons with parallel spins can be bound to pairs carrying the supercurrent over longer distances through magnets,” the article explained. “This concept may enable novel electronic devices with revolutionary properties.”

The researchers demonstrated through experiments that it was possible to create and detect spin-aligned electron pairs. Using samples of aluminium and euopiumsulfide from the Karlsruhe Institute of Technology and a scanning tunneling microscope, measurements of the charge transport were taken at low temperatures.

“The voltage dependence of the charge transport through the samples is indicative of the energy distribution of the electron pairs and allows accurate determination of the composition of the superconducting state,” the article continued. “The energy spectra predicted by the theory agree with the experimental findings, providing direct proof of the magnetic electron pairs.”

The research was recently published in Nature Communications. The abstract read:

“In conventional superconductors, electrons of opposite spins are bound into Cooper pairs. However, when the superconductor is in contact with a non-uniformly ordered ferromagnet, an exotic type of superconductivity can appear at the interface, with electrons bound into three possible spin-triplet states. Triplet pairs with equal spin play a vital role in low-dissipation spintronics.

“Despite the observation of supercurrents through ferromagnets, spectroscopic evidence for the existence of equal-spin triplet pairs is still missing.

“Here we show a theoretical model that reveals a characteristic gap structure in the quasiparticle density of states which provides a unique signature for the presence of equal-spin triplet pairs.

“By scanning tunnelling spectroscopy we measure the local density of states to reveal the spin configuration of triplet pairs. We demonstrate that the Al/EuS interface causes strong and tunable spin-mixing by virtue of its spin-dependent transmission.”