Pure nickel oxide studies rebuttal to hydrogen-induced links

Physicists at the National University of Singapore (NUS) have synthesized very pure superconducting materials and redefine the important role of hydrogen in the newly discovered superconductors of nickel oxides.

Their findings were published simultaneously in Journals Nature Communications and Physical Review Letters.

Superconductivity is an exciting phenomenon in which electrical resistance disappears and retains the potential for transformation to revolutionize energy technology. Despite its possibilities, the origin and fundamental mechanisms of superconductivity continue to be one of the greatest mysteries of physics.

More than a century after the discovery of superconductivity, only a subgroup of superconducting materials, primarily elemental metals and hydrogen-based compounds, can be explained using the 1972 Nobel Prize-winning Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity.

However, there is a large group of superconducting materials classified as “unconventional superconductors,” and this theory cannot explain the superconducting mechanism. The recently discovered nickel oxide superconductor is one such example.

In a recent study published in the journal Nature, researchers proposed that hydrogen plays an important role in the superconductivity of nickel oxide. Using an ion detection technique known as secondary ion mass spectrometry to measure hydrogen concentration, researchers have proposed a link between hydrogen and superconductivity, resulting from a mechanism consistent with BCS theory.

The research team, led by Professor Ariand of the NUS Faculty of Physics, relies on various international collaborators (Singapore’s Institute of Science and Technology (A*STAR), National Institute of Standards (NIST Institute), Harvard University, University of Southern California, Arizona State University, Carnell University, Cornell University, and the United States of America’s Synthesis Super Coindinate Renderukman’s Superconductors of Nickel Oxide.

Contrary to previous discoveries reported in nature, Professor Ariand’s team and collaborators concluded that there is an insignificant presence of hydrogen in pure nickel oxide materials. They also established that there is no correlation between hydrogen and superconductivity.

One of the authors, PhD student Lin El Chow, said, “Amazingly, hydrogen is not even present in pure superconducting nickel oxide. This observation suggests that hydrogen does not play a key role in the superconductivity origin of these materials.”

“These findings will help guide research directions to understand the fundamental superconductivity mechanisms of high critical temperature unconventional superconductors,” added Professor Ariand.