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Category: materials – Page 21

Highly twisted metamaterial rods store large amounts of energy

An international research team coordinated at KIT (Karlsruhe Institute of Technology) has developed mechanical metamaterials with a high elastic energy density. Highly twisted rods that deform helically provide these metamaterials with a high stiffness and enable them to absorb and release large amounts of elastic energy. The researchers conducted simple compression experiments to confirm the initial theoretical results. Their findings have been published in the journal Nature.

Storage of mechanical energy is required for many technologies, including springs for absorbing energy, buffers for mechanical energy storage, or flexible structures in robotics or energy-efficient machines. Kinetic energy, i.e., motion energy or the corresponding mechanical work, is converted into elastic energy in such a way that it can be fully released again when required.

The key characteristic here is enthalpy—the energy density that can be stored in and recovered from an element of the material. Peter Gumbsch, Professor for at KIT’s Institute for Applied Materials (IAM), explains that achieving the highest possible enthalpy is challenging: “The difficulty is to combine conflicting properties: high stiffness, and large recoverable strain.”

Researchers propose a simple magnetic switch using altermagnets

Controlling magnetism in a device is not easy; unusually large magnetic fields or lots of electricity are needed, which are bulky, slow, expensive and/or waste energy. But that looks soon to change, thanks to the recent discovery of altermagnets. Now scientists are putting forth ideas for efficient switches to manage magnetism in devices.

Magnetism has traditionally come in two varieties: ferromagnetism and antiferromagnetism, based on the alignment (or not) of in a material. Early last year, physicists announced experimental evidence for a third variety of magnetism: altermagnetism, a different combination of spins and crystal symmetries. Researchers are now learning how to tune altermagnets, bringing science closer towards practical applications.

We’re all familiar with ferromagnetism (FM), like a refrigerator magnet or compass needle, where magnetic moments in atoms lined up in parallel in a crystal. A second class was added about a hundred years ago called antiferromagnetism (AFM), where magnetic moments in a crystal align regularly in alternate directions on differing sublattices, so the crystal has no net magnetization, but usually does at low temperatures.

Rare quantum state spotted, thanks to thermopower signals in graphene

Such findings wouldn’t have been possible using the traditional resistivity approach. “We demonstrate that the magneto-thermopower detection of fractional quantum Hall states is more sensitive than resistivity measurements,” the researchers note.

“Overall, our findings reveal the unique capabilities of thermopower measurements, introducing a new platform for experimental and theoretical investigations of correlated and topological states in graphene systems, including moiré materials,” Ghahari concluded.

Hopefully, these findings will help us realize the true potential of the FQH effect. However, whether the same approach could be used to detect other exotic quantum states remains to be explored through further research.

Quantum Dots Rebuilt by Light in a Trillionth of a Second

Argonne scientists have unveiled new methods for controlling material properties. The breakthrough enables researchers to design materials with customized properties, offering unprecedented control over their optical and electronic behaviors. Imagine building a Lego tower with perfectly aligned

The hidden superconducting state in NbSe₂: Shedding layers and gaining insights

Researchers have discovered an unexpected superconducting transition in extremely thin films of niobium diselenide (NbSe2). Publishing in Nature Communications, they found that when these films become thinner than six atomic layers, superconductivity no longer spreads evenly throughout the material, but instead becomes confined to its surface.

This discovery challenges previous assumptions and could have important implications for understanding and developing advanced quantum technologies.

Researchers at the Hebrew University of Jerusalem have made a surprising discovery about how superconductivity behaves in extremely thin materials. Superconductors are materials that allow electric current to flow without resistance, which makes them incredibly valuable for technology. Usually, the properties of superconductors change predictably when the materials become thinner; however, this study found something unexpected.

These Electronics-free Robots Can Walk Right Off the 3D-Printer

Imagine a robot that can walk, without electronics, and only with the addition of a cartridge of compressed gas, right off the 3D-printer. It can also be printed in one go, from one material.

That is exactly what roboticists have achieved in robots developed by the Bioinspired Robotics Laboratory at the University of California San Diego. They describe their work in an advanced online publication in the journal Advanced Intelligent Systems.

To achieve this feat, researchers aimed to use the simplest technology available: a desktop 3D-printer and an off-the-shelf printing material. This design approach is not only robust, it is also cheap—each robot costs about $20 to manufacture.

Revolutionary self-healing hydrogel regenerates like human skin

Natural biological tissues, like human skin, possess a unique combination of properties that synthetic materials struggle to replicate. Skin is strong yet flexible and, most impressively, capable of self-repair. Until now, scientists have only been able to replicate either the stiffness of biological tissues or their self-healing ability—but never both at once.

Hydrogels have many advantages, such as biocompatibility, nutrient transport, and ionic conductivity. These features make them promising materials for biomedical applications, but their mechanical limitations have kept them from reaching their full potential.

Most self-healing hydrogels are too soft, with a Young’s modulus below 100 kilopascals (kPa). Others that achieve stiffness above 100 megapascals (MPa) typically lose their ability to heal.

40-Year Barrier Broken: Scientists Discover New High-Temperature Superconductor

NUS scientists created the first copper-free superconductor to work above 30 K under ambient pressure, marking a major scientific leap. This discovery may revolutionize energy-efficient electronics. Professor Ariando and Dr Stephen Lin Er Chow from the National University of Singapore (NUS) Depar