An experimental superconducting material developed in the laboratory: A study

WASHINGTON: Created by researchers superconducting material at temperatures and pressures low enough for practical use.
In an article in the journal Nature, researchers from the University of Rochester (USA) describe a substance with nitrogen. lutetium hydride (NDLH), which indicates superconductivity at 69 degrees Fahrenheit or 20.6 degrees Celsius and a pressure of 10 kilobars or 145,000 pounds per square inch or psi.
145,000 psi may still seem very high—pressure at sea level is about 15 psi, or 1 bar—strain engineering for example, include methods commonly used in chip manufacturing materials Internal chemical pressures are even higher, the study says.
“With this material, the dawn of environmental superconductivity and applied technologies has arrived,” said the team led by Ranga Dias, associate professor of mechanical engineering. physics.
Scientists have been searching for this discovery in condensed matter physics for more than a century.
Superconducting materials have two main properties: electrical resistance cancels out, and the magnetic fields produced pass around the superconducting material. Such materials allow:
1. Power lines that transmit electricity without losing up to 200 million megawatt hours (MWh) of energy generated by resistance in wires
2. Frictionless, high-speed trains
3. Available medical imaging and scanning techniques such as MRI and magnetocardiography
4. Faster, more efficient electronics for digital logic and memory device technology
Given the importance of the new discovery, Diaz and his team went to unusual lengths to document their research and avoid the criticism that followed an earlier Nature paper, which led to a retraction by the journal’s editors.
According to Diaz, that previous paper has been resubmitted to Nature with new data that corroborates the earlier work.
The new data was collected outside the lab at Argonne and Brookhaven National Laboratories (USA) in front of an audience of scientists who watched the superconductivity transition live.
A similar approach was used in the new paper.
“Everyone in the group was involved in the experiment,” says Diaz. “It was really a collective effort.”
Hydrides, made by combining rare-earth metals with hydrogen and then adding nitrogen or carbon, have given researchers a surprising “working recipe” for making superconducting materials in recent years.
In technical terms, rare earth metal hydrides form clathrate-like lattice structures, where the rare earth metal ions act as carrier donors, providing enough electrons to enhance the dissociation of H2 molecules. Nitrogen and carbon help stabilize materials.
Conclusion: low pressure is required for superconductivity to occur.
In addition to yttrium, researchers have used other rare earth metals. However, the resulting compounds are still superconducting at temperatures or pressures that are not practical for applications.
So this time, Diaz looked elsewhere on the periodic table.
Lutetius seemed like “a good candidate to try,” Diaz said.
Its f-orbital configuration has 14 highly localized fully filled electrons, which suppresses phonon (a quantum of acoustic energy) softening and provides the enhanced electron-phonon coupling required for superconductivity at ambient temperatures, he said.
“The main question is, how do we stabilize it to reduce the required pressure?” That’s where nitrogen comes into the picture,” Diaz said.
According to Diaz, nitrogen, like carbon, has a rigid atomic structure that can be used to create a more stable, lattice-like lattice within the material, and it stiffens low-frequency optical phonons.
This structure ensures the stability of superconductivity at low pressure, the study says.
Diaz’s team created a gas mixture of 99 percent hydrogen and one percent nitrogen, placed it in a reaction chamber with a pure sample of lutetium, and allowed the components to react at 392 degrees Fahrenheit, or 200 degrees Celsius, for two to three days.
The resulting lutetium-nitrogen-hydrogen compound was initially “bright bluish in color,” the paper said.
Then, when the compound was compressed in a diamond cell, a “stunning visual transformation” occurred: from blue to pink at the onset of superconductivity, then to a bright red superconducting metallic state.
“It was very bright red,” Diaz said. “I was amazed to see colors of such intensity. We jokingly proposed the code name for this state of matter – ‘reddmatter’ – after the material created by Spock in the famous 2009 Star Trek film.” Code name left.
The pressure of 145,000 psi required to induce superconductivity is about two times lower than previous low pressures developed in Diaz’s laboratory.

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