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Archive for the ‘materials’ category: Page 12

Jul 16, 2020

Superconductivity in metallic twisted bilayer graphene stabilized

Posted by in category: materials

Placing a single layer of tungsten diselenide in contact with twisted bilayer graphene enables superconductivity even for non-magic twist angles where insulating behavior is absent.

Jul 13, 2020

Underground CUPID-Mo Experiment in Search for Theorized ‘Neutrinoless’ Particle Process

Posted by in categories: materials, particle physics

Berkeley Lab researchers are part of an international team that reports a high-sensitivity measurement by underground CUPID-Mo experiment.

Nuclear physicists affiliated with the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) played a leading role in analyzing data for a demonstration experiment that has achieved record precision for a specialized detector material.

The CUPID-Mo experiment is among a field of experiments that are using a variety of approaches to detect a theorized particle process, called neutrinoless double-beta decay, that could revise our understanding of ghostly particles called neutrinos, and of their role in the formation of the universe.

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Jul 13, 2020

Scientists demonstrate a new experiment in the search for theorized ‘neutrinoless’ proc

Posted by in categories: materials, particle physics

Nuclear physicists affiliated with the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) played a leading role in analyzing data for a demonstration experiment that has achieved record precision for a specialized detector material.

The CUPID-Mo experiment is among a field of experiments that are using a variety of approaches to detect a theorized particle process, called neutrinoless double-beta decay, that could revise our understanding of ghostly particles called neutrinos, and of their role in the formation of the universe.

The preliminary results from the CUPID-Mo experiment, based on the Berkeley Lab-led analysis of data collected from March 2019 to April 2020, set a new world-leading limit for the neutrinoless double-beta decay process in an isotope of molybdenum known as Mo-100. Isotopes are forms of an element that carry a different number of uncharged particles called neutrons in their atomic nuclei.

Jul 12, 2020

Next Generation Magnetic Memory Breakthrough: Writing Data in Under a Nanosecond

Posted by in categories: computing, materials

Researchers at ETH have measured the timing of single writing events in a novel magnetic memory device with a resolution of less than 100 picoseconds. Their results are relevant for the next generation of main memories based on magnetism.

At the Department for Materials of the ETH in Zurich, Pietro Gambardella and his collaborators investigate tomorrow’s memory devices. They should be fast, retain data reliably for a long time and also be cheap. So-called magnetic “random access memories” (MRAM) achieve this quadrature of the circle by combining fast switching via electric currents with durable data storage in magnetic materials. A few years ago researchers could already show that a certain physical effect – the spin-orbit torque – makes particularly fast data storage possible. Now Gambardella’s group, together with the R&D-center IMEC in Belgium, managed to temporally resolve the exact dynamics of a single such storage event – and to use a few tricks to make it even faster.

Magnetizing with single spins.

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Jul 10, 2020

New technique turns junk into valuable graphene

Posted by in category: materials

Graphene is insanely useful, but very difficult to produce — until now.

Jul 8, 2020

Contest between superconductivity and insulating states in ‘magic angle’ graphene

Posted by in categories: materials, physics

If you stack two layers of graphene one on top of the other, and rotate them at an angle of 1.1º (no more and no less) from each other—the so-called ‘magic-angle,’ experiments have proven that the material can behave like an insulator, where no electrical current can flow, and at the same can also behave like a superconductor, where electrical currents can flow without resistance.

This major finding took place in 2018. Last year, in 2019, while ICFO researchers were improving the quality of the device used to replicate such breakthroughs, they stumbled upon something even bigger and totally unexpected. They were able to observe a zoo of previously unobserved superconducting and correlated states, in addition to an entirely new set of magnetic and topological states, opening a completely new realm of richer physics.

So far, there is no theory that has been able to explain superconductivity in magic angle graphene at the microscopic level. However, this finding has triggered many studies, which are trying to understand and unveil the physics behind all these phenomena that occur in this material. In particular, scientists drew analogies to unconventional high temperature superconductors—the cuprates, which hold the record highest superconducting temperatures, only 2 times lower than . Their microscopic mechanism of the superconducting phase is still not understood, 30 years after its discovery. However, similarly to magic angle twisted bi-layer graphene (MATBG), it is believed that an insulating phase is responsible for the superconducting phase in proximity to it. Understanding the relationship between the superconducting and insulating phases is at the center of researcher’s interest, and could lead to a big breakthrough in superconductivity research.

Jul 7, 2020

Shock-dissipating fractal cubes could forge high-tech armor

Posted by in categories: 3D printing, materials

Tiny, 3D printed cubes of plastic, with intricate fractal voids built into them, have proven to be effective at dissipating shockwaves, potentially leading to new types of lightweight armor and structural materials effective against explosions and impacts.

“The goal of the work is to manipulate the wave interactions resulting from a ,” said Dana Dattelbaum, a scientist at Los Alamos National Laboratory and lead author on a paper to appear in the journal AIP Advances. “The for how to do so have not been well defined, certainly less so compared to mechanical deformation of additively manufactured materials. We’re defining those principles, due to advanced, mesoscale manufacturing and design.”

Shockwave dispersing materials that take advantage of voids have been developed in the past, but they typically involved random distributions discovered through trial and error. Others have used layers to reverberate shock and release waves. Precisely controlling the location of holes in a material allows the researchers to design, model and test structures that perform as designed, in a reproducible way.

Jul 6, 2020

Napa-raised astronaut Kate Rubins prepares for return to International Space Station in October

Posted by in categories: biotech/medical, materials

Kate Rubins, the first Napa native to go to space, is entering the final three months of preparation for her return trip to the International Space Station where she served four years ago.

Starting Oct. 14 and continuing for about six months, her schedule will be replete with scientific work 250 miles above the Earth, dealing with materials ranging from supercold gases to stem cells. And unlike during her first stay in 2016, Rubins expects to get to work quickly, without the awkward introduction to moving about in microgravity.

“As a rookie you’re not so good at navigating and flying through the space station, so you tend to crawl hand over hand on the handrails,” the biochemist-turned-space traveler quipped during a NASA news conference last week in Houston, while recalling her original 115-day stint aboard the orbiting space platform.

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Jul 6, 2020

New insights into van der Waals materials found

Posted by in categories: materials, particle physics

Layered van der Waals materials are of high interest for electronic and photonic applications, according to researchers at Penn State and SLAC National Accelerator Laboratory, in California, who provide new insights into the interactions of layered materials with laser and electron beams.

Two-dimensional van der Waals materials are composed of strongly bonded layers of molecules with weak bonding between the layers.

The researchers used a combination of ultrafast pulses of laser light that excite the atoms in a material lattice of gallium telluride, followed by exposing the lattice to an ultrafast pulse of an . This shows the lattice vibrations in real time using and could lead to a better understanding of these materials.

Jul 3, 2020

The lightest electromagnetic shielding material in the world

Posted by in categories: chemistry, materials

Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic components or the transmission of signals. High-frequency electromagnetic fields can only be shielded with conductive shells that are closed on all sides. Often thin metal sheets or metallized foils are used for this purpose. However, for many applications such a shield is too heavy or too poorly adaptable to the given geometry. The ideal solution would be a light, flexible and durable material with extremely high shielding effectiveness.

Aerogels against electromagnetic radiation

A breakthrough in this area has now been achieved by a research team led by Zhihui Zeng and Gustav Nyström. The researchers are using nanofibers of as the basis for an aerogel, which is a light, highly porous material. Cellulose fibers are obtained from wood and, due to their , enable a wide range of chemical modifications. They are therefore a highly popular research object. The crucial factor in the processing and modification of these cellulose nanofibres is to be able to produce certain microstructures in a defined way and to interpret the effects achieved. These relationships between structure and properties are the very field of research of Nyström’s team at Empa.

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