A group of theoretical physicists from the University of Jyväskylä and Tampere University, Finland, and the Materials Physics Center in San Sebastian, Spain, explain how superconductors can carry magnetic information to much longer distances than can conventional metals. The finding could be useful in information processing that uses magnetic materials at low temperatures.
At low temperatures, some materials become superconductive, resulting in a vanishing electrical resistivity. Consequently, passing a charge current through a superconductor does not heat it up. Besides charge, electrons have other properties as well. One of them is spin, which describes the internal rotation of the electron around itself. Spin is the property needed to understand another type of state of materials: magnetism. Magnets and superconductors are rarely found in single materials. However, magnetic and superconducting materials can be placed next to each other so that they affect each other.
The new study, published in Physical Review Letters, shows how in certain circumstances superconductors can carry not only charge current between metals, but also spin currents between magnets to relatively long distances without producing excess heat. This is in contrast with ordinary conductors where such frictionless spin currents vanish within atomic distances.
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