At the University of Rochester (via Phys.org) they say they have created a superconducting material That retains its properties at sufficiently low temperatures and pressures to allow concrete applications. It could be a historic result, potentially a harbinger of great technological evolutions in various sectors, but around discovery there is some skepticism.
Before explaining the reason, let’s go into a little more detail. THE superconductorsas the name suggests, are not simple conductors but have a zero electrical resistance, i.e. they do not hinder the passage of electric chargeswhich in conductors creates the well-known phenomenon of heat dissipation.
Another feature of superconducting materials is the Meissner effect, at the base of the magnetic levitation. In practice, they can “float in the air” when accompanied by an external magnet that generates a magnetic field. This is because in superconductors the magnetic field is expelledcreating “perfect diamond”.
Superconductors could be applied in many sectors with great advantage, for example in electrical networks without losing up to 200 million megawatt hours (MWh) to electrical resistance. Another use is in magnetic levitation trainsin the creation of faster and more efficient memory and logic chipsbut also in tokamak to get the nuclear fusion. Last but not least, they might allow you to fine-tune medical imaging and scanning techniques more advanced and efficient.
Typically superconductivity is obtained only at temperatures above a certain threshold, called the critical temperature, in some cases close to absolute zero (there are various types of superconductors). Achieving it requires complex cooling solutions that drive up application costs. Eliminating the cooling problem, or minimizing it, could lead to a breakthrough.
“With this material came the dawn of superconductivity under ambient conditions and applied technologies“, declare the researchers of the team led by Ranga Dias, assistant professor of mechanical engineering and physics. In an article published in Nature, the researchers describe the qualities ofnitrogen-doped lutetium hydride (NDLH), able to show superconductivity at 69°F (20.5°C) of temperature and 10 kilobars (145,000 psi) of pressure. The latter is a value which, while it may appear high (sea level pressure is about 15 psi), it is far less than that applied in chip manufacturing.
Everything therefore appears “set up” for a result of historic significance, if not that the team led by Dias it has been in years past at the center of bitter controversy For other research on superconductorsopposed by other physicists for the processing and analysis methods used, so much so that Nature had to remove the study, which was then resubmitted with new data to validate the previous work, under the supervision of other scientists.
For the latter study, Dias and his team say they have took a similar approach, which is they collected the data in front of an audience of scientists who saw the superconducting transition live. Therefore, unless other criticisms emerge on methodology, numbers and various aspects, we must take the results for granted.
Researchers, having analyzed several rare earths, came to the conclusion that lutetium seemed like a good candidate for making a superconductor at acceptable temperatures and pressures. The metallic element has “14 highly localized fully filled electrons in its electron configuration of its f-orbitals which suppress phonon softening and provide an improvement in the electron-phonon coupling necessary for superconductivity to occur at room temperature.”
To achieve stabilization and lower the required pressure the researchers turned to thenitrogen. Like carbon, nitrogen has a rigid atomic structure that it can be used to create a more stable lattice, resembling a cage within a material and hardens low-frequency optical phonons. This structure provides the stability for superconductivity to occur at lower pressures.
Dias team created a gas mixture of 99% hydrogen and 1% nitrogenplaced it in a reaction chamber with a pure sample of lutetium and allowed the components to react for two to three days at 392°F (200°C).
The resulting lutetium-nitrogen-hydrogen compound was initially a “brilliant bluish color,” but when it was compressed in a diamond anvil cell, a “striking visual transformation” occurred: from blue to pink at the beginning of the superconductivity, and then to a non-superconducting bright red metallic state.
“It was a very bright red,” Dias explained. “I was shocked to see colors of this intensity. We have jokingly suggested a code name for the material in this state – ‘reddmatter’ – as a material created by Spock in the 2009 film Star Trek”.
The 145,000 psi of pressure required to induce superconductivity is nearly two orders of magnitude lower than required in other past studiesand this allowed Dias and his team to obtain a superconductor capable of existing both at ambient temperatures and at pressures low enough for practical applications.
Professor Dias and his team are now exploring the possibility of train machine learning algorithms with the data accumulated to track down other possible similar materials. “In everyday life aWe have many different metals that we use for different applications, so we will also need different types of superconducting materials“, he has declared.
Study co-author Keith Lawlor has already begun developing algorithms and doing the necessary calculations with resources from the University of Rochester’s Center for Integrated Research Computing.
