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Category: materials – Page 122

SOM-backed Prometheus Materials turns algae-like composite into masonry blocks

Colorado-based Prometheus Materials has developed masonry blocks from a low-carbon cement-like material grown from micro–algae.

The blocks, which meet the American Society for Testing and Materials (ASTM) standards, were made using an organic cement-like material grown in bioreactors that reproduces itself in ways similar to coral.

“Coral reefs, shells, and even the limestone we use to produce cement today show us that nature has already figured out how to bind minerals together in a strong, clever, and efficient way,” said Prometheus Materials co-founder Wil V Srubar III.

Detection of the Orbital Hall Effect

Two different experiments on two different transition metals reveal that a current of electron orbital angular momentum flows in response to an electric field.

In the spin Hall effect, an applied electric field drives a current of electron spin in a direction transverse to the field. In a transition metal, theorists predict that an orbital angular momentum (OAM) current can also flow. Now two groups have independently observed this so-called orbital Hall effect (OHE) [1, 2]. These observations supplement one made by a third group earlier this year [3]. Together these demonstrations constitute a step toward the development of “orbitronic” devices based on an electron’s orbital degree of freedom.

For their demonstration, Giacomo Sala of the Swiss Federal Institute of Technology (ETH) in Zurich and his colleagues turned to a phenomenon known as Hanle magnetoresistance. In a conductor, when a magnetic field is applied parallel to the direction of electron OAM, orbital moments should accumulate at the edges of the sample because of the OHE. If instead the field is applied perpendicular to electron OAM, the orbital moments should precess. The orbital moments should then fall out of phase with each other, which boosts the material’s magnetoresistance. The team observed these effects in thin films of manganese [1].

NASA’s recovered Bennu asteroid samples show evidence of carbon and water, scientists say

Rocks and soil collected from the asteroid Bennu and brought back to Earth last month by NASA’s OSIRIS-REx probe are rich in carbon and contain water-bearing clay minerals that date back to the birth of the solar system, scientists said Wednesday. The discovery gives critical insight into the formation of our planet and supports theories about how water may have arrived on Earth in the distant past.

The clay minerals “have water locked inside their crystal structure,” said Dante Lauretta, a planetary scientist at the University of Arizona and the principal investigator of the asteroid sample return mission, while revealing initial photographs of the material.

Elevating neuromorphic computing using laser-controlled filaments in vanadium dioxide

In a new Science Advances study, scientists from the University of Science and Technology of China have developed a dynamic network structure using laser-controlled conducting filaments for neuromorphic computing.

Neuromorphic computing is an emerging field of research that draws inspiration from the to create efficient and intelligent computer systems. At its core, relies on , which are computational models inspired by the neurons and synapses in the brain. But when it comes to creating the hardware, it can be a bit challenging.

Mott materials have emerged as suitable candidates for neuromorphic computing due to their unique transition properties. Mott transition involves a rapid change in electrical conductivity, often accompanied by a transition between insulating and metallic states.

Realizing attosecond core-level X-ray spectroscopy for the investigation of condensed matter systems

The many-body interaction of charges (electrons) and nuclei (phonons) plays a critical role in determining the properties and functionalities of molecules and solids. The exact correlated motion of these particles gives rise to different conductivity, energy storage capabilities, phase transitions, and superconductivity. Now, the team of ICREA Prof. at ICFO Jens Biegert has developed attosecond soft X-ray core-level spectroscopy as a method to observe the correlated interaction between charges and phonons in real time.

Attosecond soft X-ray spectroscopy relies on the use of ultrashort pulses with photon energies that cover the entire water-window range. Through high-order with an intense few-cycle short-wavelength infrared pulse, the team has successfully generated a bright 165 attosecond pulse with photon energies of up to 600 eV. By directing this ultrashort soft X-ray pulse into the sample, the high-energy photons can excite the electrons in the K-shell or L-shell to unoccupied or continuum states.

This soft X-ray absorption spectroscopy provides researchers with a powerful tool for unraveling the electronic and structural characteristics of the material at the same time.

Researchers realize orientation control of cMOF nanofilms

Researchers from the Institute of Process Engineering (IPE) of the Chinese Academy of Sciences and Kyoto University have proposed a strategy to grow “face-on” and “edge-on” conductive metal-organic frameworks (cMOF) nanofilms on substrates by controlling the “stand-up” behaviors of ligands on various surfaces to overcome the difficulty in the orientation control of such films.

They established operando characterization methodology using and X-ray to demonstrate the softness of the crystalline nanofilms and reveal their unique conductive functions. The study was published in Proceedings of the National Academy of Sciences on Sept. 25.

CMOFs have great potential for use in modern electrical devices due to their porous nature and the ability to conduct charges in a regular network. cMOFs applied in normally hybridize with other materials, especially substrates. Therefore, precisely controlling the between a cMOF and a substrate is crucial.

Ionic crystal generates molecular ions upon positron irradiation

The positron, the antiparticle of the electron, has the same mass and charge as that of an electron but with the sign flipped for the charge. It is an attractive particle for scientists because the use of positrons has led to important insights and developments in the fields of elementary particle physics, atomic physics, materials science, astrophysics, and medicine.

For instance, positrons are known to be components of antimatter. They are also powerful in detecting lattice defects in solids and semiconductors and in structural analysis of the topmost surface of crystals.

Positronic compounds, namely bound states of positrons with regular atoms, molecules, or ions, represent an intriguing aspect of –matter interactions and have been studied experimentally via observation of positron annihilation in gases. It may be possible to generate new molecules and ions via the formation of positron compounds, but no research has ever been done from such a perspective.