Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: materials – Page 6

Shaking magnets with ultrafast light pulses reveals surprising spin control

An international team of researchers led by Lancaster University has discovered a highly efficient mechanism for shaking magnets using very short light pulses, shorter than a trillionth of a second. Their research is published in Physical Review Letters.

The discovery of new fundamental properties and phenomena in magnetic materials is essential for the development of faster and energy-efficient devices.

Using a very short electromagnetic pulse to shake the magnetization, researchers investigated its effect on the magnetization steering angle in two similar magnetic materials with different electronic orbitals. After shaking the magnet and subsequently analyzing its magnetic state, they found that interaction between orbital motion and spinning enables a 10-fold larger spin deflection by the light pulse than the one without such interactions.

US develops method to spot illegal nuclear material origins in 30 mins

A simple instrument like mass spectrometer can revolutionize how unknown samples are investigated in the future.

A new method developed by researchers at the Los Alamos National Laboratory (LANL) can spot the origins of illegal nuclear material in just 30 minutes. Requiring only a relatively simple instrument, such as a mass spectrometer, the method can help identify the source of any nuclear material outside regulatory control.

According to the International Atomic Energy Agency (IAEA), theft or improper disposal can result in nuclear and radiological material falling out of regulatory control. In 2,024,124 such incidents were reported to the IAEA, of which at least three were linked to “trafficking or malicious use”

Earlier this year, a leader of a crime syndicate pleaded guilty to trafficking nuclear material in a New York court. The accused had discussed sale of yellowcake uranium with an undercover agent.

Scientists create stable, switchable vortex knots inside liquid crystals

The knots in your shoelaces are familiar, but can you imagine knots made from light, water, or from the structured fluids that make LCD screens shine?

They exist, and in a new Nature Physics study, researchers created particle-like so-called “vortex knots” inside chiral nematic liquid crystals, a twisted fluid similar to those used in LCD screens. For the first time, these knots are stable and could be reversibly switched between different knotted forms, using electric pulses to fuse and split them.

“These particle-like topological objects in liquid crystals share the same kind of topology found in theoretical models of glueballs, experimentally-elusive theoretical subatomic particles in high-energy physics, in hopfions and heliknotons studied in light, magnetic materials, and in vortex knots found across many other systems,” explains Ivan Smalyukh, director of the Hiroshima University WPI-SKCM² Satellite at the University of Colorado Boulder and a professor in CU Boulder’s Department of Physics.

Room-temperature electron behavior defies expectations, hinting at ultra-efficient electronics

Scientists have discovered a way to efficiently transfer electrical current through specific materials at room temperature, a finding that could revolutionize superconductivity and reshape energy preservation and generation.

The paper is published in the journal Physical Review Letters.

The much-sought-after breakthrough hinges on applying high pressure to certain materials, forcing their electrons closer together and unlocking extraordinary electronic behaviors.

Engineered material uses light to destroy PFAS and other contaminants in water

Materials scientists at Rice University and collaborators have developed a material that uses light to break down a range of pollutants in water, including per- and polyfluoroalkyl substances, or PFAS, the “forever chemicals” that have garnered attention for their pervasiveness.

Advanced optical model clarifies how complex materials interact with polarized light

Scientists at the University of Oxford demonstrate an approach to interpreting how materials interact with polarized light, which could help advance biomedical imaging and material design.

Their work, reported in Advanced Photonics Nexus, focuses on improving how researchers analyze a key optical property known as the retarder.

In optics, a retarder is a material or device that changes the way light waves are oriented as they pass through. Light waves have an orientation called polarization, and a retarder shifts the phase between different components of that light—essentially delaying one part of the wave compared to another.

Epitaxial multilayer MoS2 wafers promise high-performance transistors

Two-dimensional (2D) semiconductors, such as molybdenum disulfide (MoS2), enable unprecedented opportunities to solve the bottleneck of transistor scaling and to build novel logic circuits with faster speeds, lower power consumption, flexibility and transparency, benefiting from their ultra-thin thickness, dangling-bond-free flat surface and excellent gate controllability.

Tremendous efforts have been devoted to exploring the scaled-up potentials of MoS2, including both wafer-scale synthesis of high-quality materials and large-area devices. For instance, four-inch wafer-scale monolayer MoS2 with large domain sizes (up to ~300 μm) and record-high electronic quality (average field-effect mobility of ~80 cm2·V-1 ·s-1) has already been demonstrated via van der Waals epitaxial growth.

In terms of a further improvement of the electronic quality of the large-scale monolayer MoS2, structural imperfections should be eliminated as much as possible; however, there is not much space left for monolayer MoS2 after ten years of synthesis optimizations in this field. Another key direction is to switch to multilayer MoS2, e.g., bilayers and trilayers, since they have intrinsically higher electronic quality than monolayers and thus are conducive to higher-performance devices and logic circuits. However, due to the fundamental limitation of thermodynamics, it is still a great challenge to realize wafer-scale multilayer MoS2 with high-quality and large-scale uniformity.

Graphene membranes offer efficient, low-cost option for industrial CO₂ capture

Carbon capture is becoming essential for industries that still depend on fossil fuels, including the cement and steel industries. Natural-gas power plants, coal plants, and cement factories all release large amounts of CO₂, and reducing those emissions is difficult without dedicated capture systems. Today, most plants rely on solvent-based systems that absorb CO₂, but these setups use a lot of heat, require major infrastructure, and can be costly to run.

A smaller, electricity-driven alternative is what the field calls a “membrane” system. A membrane works like an ultra-fine filter that lets certain gases slip through more easily than others, separating CO₂ from the rest of the flue gas. The problem is that many membranes lose efficiency when CO₂ levels are low, which is common in natural-gas plants, and this limits where they can be used.

A new study at EPFL has now analyzed how a new membrane material, pyridinic-graphene, could work at scale. This is a single-layer graphene sheet with tiny pores that favor CO₂ over other gases. The researchers combined experimental performance data with modeling tools that simulate real operating conditions, such as energy use and gas flow. They also explored a wide range of cost scenarios to see how the material might behave once deployed in commercial plants.

Dual substitution induces room-temperature ferromagnetism and negative thermal expansion in BiFeO₃

Using a dual-cation substitution approach, researchers at Science Tokyo introduced ferromagnetism into bismuth ferrite, a well-known and promising multiferroic material for next-generation memory technologies. By replacing ions at both the bismuth and iron sites with calcium ions and heavier elements, they modified the spin structure and achieved ferromagnetism at room temperature. Additionally, negative thermal expansion was observed. This ability to engineer magnetism and thermal expansion in a multiferroic material aids in realizing future memory devices.

Multiferroic materials, which show both ferroelectricity and ferromagnetism, hold strong potential for use in low-power memory devices where information can be written electrically and read magnetically. Among these materials, bismuth ferrite (BiFeO3) is one of the most widely studied because it combines ferroelectricity with antiferromagnetism at room temperature.

However, BiFeO3 naturally forms a cycloidal spin structure, which is a wave-like pattern of rotating spins. This pattern cancels out any net magnetization and makes the material difficult to use in magnetic devices.

New window insulation blocks heat, but not your view

Physicists at the University of Colorado Boulder have designed a new material for insulating windows that could improve the energy efficiency of buildings worldwide—and it works a bit like a high-tech version of Bubble Wrap.

The team’s material, called Mesoporous Optically Clear Heat Insulator (MOCHI), comes in large slabs or thin sheets that can be applied to the inside of any window. So far, the team only makes the material in the lab, and it’s not available for consumers. But the researchers say MOCHI is long-lasting and is almost completely transparent.

That means it won’t disrupt your view, unlike many insulating materials on the market today.

/* */