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Category: materials – Page 2

A new route to electrically controlled helimagnetic structures

Advanced magnetic memory and spintronic devices rely on the ability to control magnetic states using electricity. Today, such technologies work by manipulating relatively simple magnetic structures found in ferromagnets, where all the magnetic moments point the same way. However, researchers are becoming increasingly interested in controlling more complex magnetic systems because these could offer higher information density and improved efficiency.

Helimagnets are a prime example of such systems. In these materials, the magnetic moments form spiral or helical patterns that wind through the material. The direction in which these magnetic patterns propagate plays an important role in determining the material’s electrical and magnetic behavior.

However, researchers had not established a reliable way to reversibly control the orientation of helical magnetic structures using an electric current, and current-driven techniques developed for ferromagnets do not directly carry over to helimagnetic systems.

Neutron imaging reveals how water limits CO₂ storage in recycled concrete

The construction sector faces two problems at once: it emits large amounts of CO₂ and produces vast quantities of concrete waste. But what if part of that waste could be used to trap carbon instead of ending up as rubble?

That is the idea behind accelerated carbonation.

Crushed recycled concrete can be exposed to CO₂-rich gas, allowing carbon dioxide to react with the old cement paste and become locked into stable mineral compounds. In principle, this could help reduce the environmental impact of construction while giving demolition waste a second life.

Quantum material opens new path for studying unusual electronic behavior

The work lays the foundation to build a new platform to explore phenomena that could power devices capable of transporting and grouping electrical signals and quantum states in ways not traditionally achievable without relying on optical or engineered systems. The team detailed its findings in a paper published in Science Advances.

Non-Hermitian physics refers to systems that exhibit behaviors not found in conventional physical models, explained Morteza Kayyalha, assistant professor of electrical engineering at Penn State and corresponding author on the paper. These systems can display unusual behaviors, such as enhanced responses to perturbations and external stimuli. They can also demonstrate the non-Hermitian skin effect, where quantum states—which researchers can use to predict the physical properties of a material—become concentrated near a specific boundary or point in the material, rather than spreading uniformly throughout.

Catching hydrogen in the act: Tracking the absorption process over time

If you’re looking for hydrogen on the elemental chart, it won’t take you long to find it. It is right there at the beginning, the lightest possible material. One electron, one proton, one neutron. Simple, minimalistic, the Marie Kondo of the elemental chart, but with enormous potential in terms of possible technological applications.

A very prominent example interests every single one of us: Let’s look into the daytime sky.

If we think of the sun as a furnace, then hydrogen atoms are the coal ingots.

Metallic rutile oxides break the rules of cooling

Physicists have long puzzled over a strange contradiction inside a family of minerals called rutile oxides. These materials all share the same crystal structure—but while some of them, like titanium dioxide, are firmly insulating, others, like ruthenium dioxide, conduct electricity like a metal. So far, physicists have had little idea of why this happens.

In a new study published in Physical Review B, researchers led by Kaushik Sen at the Indian Institute of Technology Delhi traced the answer back to phonons: the tiny vibrations that ripple through a material’s atomic lattice.

Their discovery reveals that metallic rutile oxides develop a fundamentally different relationship between electrons and phonons as they cool—settling a long-running scientific dispute along the way.

JWST finds the most distant barred galaxy candidate in the early universe

Astronomers using the James Webb Space Telescope have identified what may be the most distant barred spiral galaxy ever discovered, dating to a time less than 1.2 billion years after the Big Bang. The paper outlining its properties was posted to the arXiv preprint server on June 23.

Stellar bars are elongated formations of stars that stretch across a galaxy’s central region, spinning together as a single, unified structure. Through this rotation, they function much like a funnel, channeling gas toward the galactic center. This can ignite bursts of star formation, supply material to the central black hole and contribute to the buildup of a compact core. Such structures are common among galaxies in the local universe, and our own Milky Way is one example of a barred galaxy.

But bars don’t just form anywhere. They take shape in galaxies where stars move in smooth and orderly fashion, with something called a dynamically “cold” disk. Early-universe galaxies were the opposite: turbulent and gas-rich, constantly disrupted by mergers and bursts of star formation, conditions that should keep disks “hot” and unsettled for billions of years.

Optical writing of antiferromagnets points toward new storage devices and energy efficient information systems

A German-Japanese research team involving the University of Augsburg has made a significant breakthrough in the use of antiferromagnets. For the first time, the team has succeeded in writing magnetic information using only ultrashort laser pulses—without the need for electric currents or magnetic fields.

Antiferromagnetic materials are considered promising for the next generation of data storage devices because they react particularly quickly and are insensitive to external disturbances. Until now, however, their application has been limited because their magnetic states are difficult to control precisely.

The research team led by experimental physicist Prof. Dr. István Kézsmárki has now developed a new method in which it is not the polarization of the light, but its direction of propagation (“pulse”), that is used for control. Through targeted irradiation, it is possible to switch between different magnetic states and write information. Furthermore, this information can also be read out using purely optical means. The paper is published in the journal Nature Materials.

Atomic ‘domino effect’ found to drive phase changes in a two-dimensional crystal

Phase transformations—in which a material changes from one crystal structure to another, thereby acquiring dramatically different properties—are ubiquitous in nature. Understanding the microscopic mechanisms of these transformations is essential for controlling material properties and designing functional devices.

A research team led by Profs. Chen Xingqiu and Sun Yan from the Institute of Metal Research (IMR) of the Chinese Academy of Sciences, in collaboration with Prof. Niu Haiyang from Northwestern Polytechnical University, has uncovered a previously unknown phase transformation mechanism in monolayer molybdenum telluride (MoTe2).

The study, published in Proceedings of the National Academy of Sciences on June 29, reveals a phase transformation pathway that is fundamentally distinct from the conventional martensitic model, in which many atoms move together through concerted shear displacements.

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