Protein in squid teeth could hold the solution for self-healing materials.
Category: materials – Page 219
Forty-five years after superconductivity was first discovered in metals, the physics giving rise to it was finally explained in 1957 at the University of Illinois at Urbana-Champaign, in the Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity.
Thirty years after that benchmark achievement, a new mystery confronted condensed matter physicists: the discovery in 1987 of copper-oxide or high-temperature superconductors. Now commonly known as the cuprates, this new class of materials demonstrated physics that fell squarely outside of BCS theory. The cuprates are insulators at room temperature, but transition to a superconducting phase at a much higher critical temperature than traditional BCS superconductors. (The cuprates’ critical temperature can be as high as 170 Kelvin—that’s −153.67°F—as opposed to the much lower critical temperature of 4 Kelvin—or −452.47°F—for mercury, a BCS superconductor.)
The discovery of high-temperature superconductors, now more than 30 years ago, seemed to promise that a host of new technologies were on the horizon. After all, the cuprates’ superconducting phase can be reached using liquid nitrogen as a coolant, instead of the far costlier and rare liquid helium required to cool BCS superconductors. But until the unusual and unexpected superconducting behavior of these insulators can be theoretically explained, that promise remains largely unfulfilled.
The possibility of achieving room temperature superconductivity took a tiny step forward with a recent discovery by a team of Penn State physicists and materials scientists.
The surprising discovery involved layering a two-dimensional material called molybdenum sulfide with another material called molybdenum carbide. Molybdenum carbide is a known superconductor—electrons can flow through the material without any resistance. Even the best of metals, such as silver or copper, lose energy through heat. This loss makes long-distance transmission of electricity more costly.
“Superconductivity occurs at very low temperatures, close to absolute zero or 0 Kelvin,” said Mauricio Terrones, corresponding author on a paper in Proceedings of the National Academy of Sciences published this week. “The alpha phase of Moly carbide is superconducting at 4 Kelvin.”
Materials scientists studying recharging fundamentals made an astonishing discovery that could open the door to better batteries, faster catalysts and other materials science leaps.
Scientists from the University of California San Diego and Idaho National Laboratory scrutinized the earliest stages of lithium recharging and learned that slow, low-energy charging causes electrodes to collect atoms in a disorganized way that improves charging behavior. This noncrystalline “glassy” lithium had never been observed, and creating such amorphous metals has traditionally been extremely difficult.
The findings suggest strategies for fine-tuning recharging approaches to boost battery life and—more intriguingly—for making glassy metals for other applications. The study was published on July 27 in Nature Materials.
Discovery by scientists at Berkeley Lab, UC Berkeley could help find silicon’s successor in race against Moore’s Law.
In the search for new materials with the potential to outperform silicon, scientists have wanted to take advantage of the unusual electronic properties of 2D devices called oxide heterostructures, which consist of atomically thin layers of materials containing oxygen.
Scientists have long known that oxide materials, on their own, are typically insulating – which means that they are not electrically conductive. When two oxide materials are layered together to form a heterostructure, new electronic properties such as superconductivity – the state in which a material can conduct electricity without resistance, typically at hundreds of degrees below freezing – and magnetism somehow form at their interface, which is the juncture where two materials meet. But very little is known about how to control these electronic states because few techniques can probe below the interface.
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Jacques Cousteau’s grandson is pushing for the construction of a real-life Sealab 2021. The proposed undersea laboratory is so foreign to our idea of marine studies that it’s being likened to a space station that’s also under the ocean.
The station is named Proteus, not for the changing nature of matter (like a new uncuttable material with the same name), but for the shepherd of the sea. By placing a station 60 feet underwater around the Caribbean island of Curacao, sponsoring Northeastern University says it can reduce divers’ high amount of overhead time and reduce the danger of nitrogen-induced health effects.
The magnetic properties of a chromium halide can be tuned by manipulating the non-magnetic atoms in the material, a team, led by Boston College researchers, reports in the most recent edition of Science Advances.
The seemingly counter-intuitive method is based on a mechanism known as an indirect exchange interaction, according to Boston College Assistant Professor of Physics Fazel Tafti, a lead author of the report.
An indirect interaction is mediated between two magnetic atoms via a non-magnetic atom known as the ligand. The Tafti Lab findings show that by changing the composition of these ligand atoms, all the magnetic properties can be easily tuned.
Apple, the world’s largest technology company by revenue, is already carbon neutral for its corporate facilities, a goal achieved in April 2020. However, the consumer electronics giant now intends to make every product and its entire supply chain – from manufacturing to transportation to end-of-life material recovery – net zero by 2030.
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The researchers also speculated about weaving some of the material into spacesuit fabric, New Scientist reports, but the main draw of their work is that damaged fungus shields would be able to grow back.
“What makes the fungus great is that you only need a few grams to start out,” Stanford researcher and study co-author Nils Averesch told New Scientist. “It self-replicates and self-heals, so even if there’s a solar flare that damages the radiation shield significantly, it will be able to grow back in a few days.”