Researchers synthesise room temperature superconducting material

Joanna Estrada
October 16, 2020

These were the details of the news Team makes superconductors the "Holy Grail" for this day.

United States physicists have created a material that appears to conduct electricity with ideal efficiency at 15 degrees Celsius - the first-ever room-temperature superconductor.

Three years later, Eremets and his team raised the temperature further to -23 degree Celsius, but with the addition of a hydrogen-rich compound containing lanthanum.

"Because of the limits of low temperature, materials with such extraordinary properties have not quite transformed the world in the way that many might have imagined", physicist Ranga Dias of the University of Rochester said in a press statement.

Superconductivity was first discovered in 1911. It took temperature way below zero degrees to avoid resistance. Usually, the flow of an electrical current encounters some degree of resistance - a bit like how air resistance pushes back on a moving object, for example.

Now, for the first time, scientists have reported developing a material that could conduct electricity without offering any resistance at a temperature of about 15 degree Celsius. Thus, the team studied additional samples of the material and investigated its magnetic properties. The team also applied an oscillating magnetic field to the material and showed that when the material became a superconductor, it expelled that magnetic field from its interior, another sign of superconductivity. So tackling this loss could potentially save billions of dollars and have an effect on the climate. But there's a big problem. Keeping materials at these temperatures is hard and expensive, which has proven a practical barrier to broader implementation.

The following best thing is a metal that is wealthy in hydrogen, similar to the hydrogen sulfide and lanthanum hydride utilized in past examinations. The regular element there is hydrogen, the lightest element in nature. But hydrogen as a gas is an insulator; in order to make it superconducting, it needs to be metalised under huge pressures.

"To have a high temperature superconductor, you want stronger bonds and light elements", he says.

"This is certainly a very exciting result", says condensed matter physicist Rongkun Zheng from the University of Sydney, who was not involved in the study. "Hydrogen is the lightest material, and the hydrogen bond is one of the strongest".

Physicists have reached a major milestone, achieving superconductivity at room temperature, bringing humanity one major step closer towards several revolutionary technologies which would change life as we know it. Instead, physicists now have a new goal: to create a room temperature superconductor that works without tightening, Somayazulu says.

Researchers have also explored copper oxides and iron-based chemicals as potential candidates for high temperature superconductors in recent years.

In 2017, physicists reported metallic hydrogen at pressures between 465 and 495 gigapascals and temperatures of 5.5 Kelvin (-267.65 °Cs; -449.77 °F).

There's just one catch: it requires crushing pressures, equivalent to about two-thirds of the pressure at the Earth's core.

And so, Dias's lab at Rochester has pursued a "paradigm shift" in its approach, using as an alternative, hydrogen-rich materials that mimic the elusive superconducting phase of pure hydrogen, and can be metalized at much lower pressures.

Other coauthors on the paper include lead author Elliot Snider '19 (MS), Nathan Dasenbrock-Gammon '18 (MA), Raymond McBride '20 (MS), Kevin Vencatasamy '21, and Hiranya Vindana (MS), all of the Dias lab; Mathew Debessai (Ph.D) of Intel Corporation, and Keith Lawlor (Ph.D) of the University of Nevada Las Vegas. First, they tried combining the hydrogen with yttrium to create yttrium superhydride. This carbonaceous sulfur hydride demonstrated superconductivity at around 58 °F (14.5 °C), and at pressures of around 39 million psi.

Next, Snider and his group took a stab at consolidating carbon, sulfur, and hydrogen to make carbonaceous sulfur hydride.

The superconductor was made between two diamond "anvils". What's more, they discovered it, at 270 gigapascals, and 15 degrees Celsius.

Obviously, it's still a way off being useable in everyday circumstances. The sample sizes were microscopic, between 25 and 35 microns, and the pressure at which superconductivity emerged still rather impractical. Further "compositional tuning" of this combination of elements may be the key to achieving superconductivity at even higher temperatures, they add. They also note that fine-tuning the makeup of ingredients could allow for superconductivity at even higher temperatures.

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