DEC 06, 2018

Rare Uranium Compounds Capable of High-temperature Superconductivity at Near Normal Pressure

WRITTEN BY: Daniel Duan

Uranium is often associated with nuclear fuel materials, but very soon they could be used to power a new wave of industrial revolution. Scientists from Russia, China, and the U.S. have uncovered an extraordinary property of a type of uranium compounds known as the uranium hydride. These compounds can act like a superconductor at near normal atmospheric pressure.

Superconductivity happens electrons zip through a material with zero resistance, giving rise to the expulsion of magnetic flux fields (cue the frozen, levitating magnet). Superconducting materials are expected to revolutionize the electricity delivery grids, digital computers, power storage devices, and the electric transportation system.

The problem with superconductivity achieved so far is that most experiments were conducted between the absolute zero and  30 Kelvin (-406 F). Since the 1980s, scientists have uncovered an increasing number of new materials that can achieve high-temperature superconductivity.

The most recent record was held by a study from 2014. A Canada-China collaboration demonstrated superconductivity at 203 Kelvin (-94 Fahrenheit), using condensed hydrogen sulfide. But there was a catch--it was under an extremely high pressure, 150 gigapascals (an equivalent of 1.5 million times of an atmospheric pressure).

But this previous success did draw the Russian-led team's attention to the hydride type compounds. They focused at uranium, a bulky actinide. Their modeling algorithm predicted that uranium hydrides can exist, and also some variant of them could be superconducting under much lower pressures, which they managed to confirm through experiments.

Their study showed that metal hydrides hold as much potential as non-metals in terms of high-temperature superconductivity. Yet, the highest temperature for these new hydrides to work is still nowhere close to ambient temperature: 54 Kelvin (-362 Fahrenheit). 

Nonetheless, the tri-nation group thinks they have got a lot of room for improvement, that is to jack up the temperature for superconductivity to happen, by adding other elements into the uranium compounds. More importantly,  according to the researchers, it is essential to find the key mechanism that underpins the superconductive property of their uranium compounds as well as other high-temperature superconductors.

This research is published in Science Advances.

Source: Seeker via Youtube