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Archive for the ‘materials’ category: Page 41

Mar 9, 2024

In Search of Muons: New Study Unveils Unexpected Behavior in Magnetic Oxides

Posted by in category: materials

Muon spectroscopy serves as a crucial experimental method for exploring the magnetic characteristics of materials. This technique involves embedding a spin-polarized muon within the crystal lattice and observing the impact of the surrounding environment on its behavior. It operates on the principle that the muon will settle into a specific location predominantly influenced by electrostatic forces, a position that can be pinpointed through the calculation of the material’s electronic structure.

But a new study led by scientists in Italy, Switzerland, UK, and Germany has found that, at least for some materials, that is not the end of the story: the muon site can change due to a well-known but previously neglected effect, magnetostriction.

Pietro Bonfà from the University of Parma, lead author of the study just published in Physical Review Letters, explains that his group and their colleagues at the University of Oxford (UK) have been using density-functional theory (DFT) simulations for at least a decade to find muon sites.

Mar 9, 2024

Spontaneous curvature the key to shape-shifting nanomaterials, finds study

Posted by in categories: materials, nanotechnology

Inspired by nature, nanotechnology researchers have identified ‘spontaneous curvature’ as the key factor determining how ultra-thin, artificial materials can transform into useful tubes, twists and helices.

Greater understanding of this process—which mimics how some seed pods open in nature—could unlock an array of new chiral materials that are 1,000 times thinner than a , with the potential to improve the design of optical, electronic and mechanical devices.

Chiral shapes are structures that cannot be superimposed on their mirror image, much like how your left hand is a of your right hand but cannot fit perfectly on top of it.

Mar 8, 2024

MIT’s new plant-based material could replace plastics

Posted by in categories: materials, sustainability

Using cellulose from trees and a synthetic polymer, MIT researchers have created a material that “is stronger and tougher than some types of bone, and harder than typical aluminum alloys,” the university announced.

The researchers hope their compound could lead to better, more sustainable plastics in the future. Currently, the material shrinks while drying, making printing anything large out of it difficult.

“If you could avoid shrinkage, you could keep scaling up, maybe to the meter scale,” said MIT’s Abhinav Rao. “Then, if we were to dream big, we could replace a significant fraction of plastics with cellulose composites.”

Mar 8, 2024

Abnormal Thin Film LK99 Result from Korea Excites Chinese Superconductor Researchers

Posted by in categories: chemistry, materials

There was a APS presentation by Ulsan Korea University researchers.

It is being reported that numerous comments on the Chinese website Zhihu imply that the University of Ulsan’s data plot is so important that a certain superconductivity expert saw the decisive signal proving LK99’s superconductivity in the graph’s temperature rise curve near 200K.

Nextbigfuture does not understand how a resistance rise implies any superconductivity but it is a thin film LK99-related material. Previously, LK99 thin film analysis by the original Korea researchers had found superconducting levels of resistance with chemically vapor deposited thin film.

Mar 5, 2024

Researchers develop amphibian-inspired camouflage skin

Posted by in category: materials

Inspired by amphibians such as the wood frog, investigators designed and synthesized a new type of camouflage skin involving one-dimensional photonic crystal structures assembled in three-dimensional flexible gels.

As described in Advanced Optical Materials, the camouflage skin can quickly recognize and match the background by modulating the optical signals of external stimuli.

It demonstrated excellent mechanical performance, self-adaptive camouflage capabilities in response to complex surroundings, and long-term stability in real-world living environments. Bright structural color and mechanical flexibility were maintained even at temperatures as low as-80℃

Mar 2, 2024

Scientists Discover Bizarre Material Where Electrons Stand Still

Posted by in categories: materials, quantum physics

Scientists at Rice University have uncovered a first-of-its-kind material: a 3D crystalline metal in which quantum correlations and the geometry of the crystal structure combine to frustrate the movement of electrons and lock them in place.

The find is detailed in a study published in Nature Physics. The paper also describes the theoretical design principle and experimental methodology that guided the research team to the material. One part copper, two parts vanadium, and four parts sulfur, the alloy features a 3D pyrochlore lattice consisting of corner-sharing tetrahedra.

Mar 2, 2024

Van der Waals quaternary oxides for tunable low-loss anisotropic polaritonics

Posted by in category: materials

Tellurite molybdenum quaternary oxides, a family of van der Waals materials, show slow group velocity and long lifetimes with promising implications for tunable low-loss anisotropic polaritonics.

Mar 2, 2024

Superconductivity in a van der Waals layered quasicrystal

Posted by in categories: materials, space

Recent theoretical studies36,37,38 have revealed that quasicrystalline superconductors exhibit several unconventional behaviors that are typically not observed in other known superconductors in periodic and disordered systems, thus opening a new field in the research of superconductivity. Nagai36 has studied superconducting tight-binding models of Penrose and Ammann Beenker lattices (typical two-dimensional quasicrystalline lattices) and demonstrated an intrinsic vortex pinning due to spatially inhomogeneous superconducting order parameter. Such an inhomogeneous order parameter arises from the quasicrystalline structural order, and therefore, the vortex pinning occurs without an impurity or defect. Sakai et al37. have investigated quasicrystalline superconductivity using an attractive Hubbard model on a Penrose lattice using the real-space dynamical mean-field theory. Unconventional spatially-extended Cooper pairs were formed; the sum of the momenta of the Cooper pair electrons was nonzero, in contrast to the zero total momentum of the Cooper pair in the conventional BCS superconductivity. Such a nonzero total momentum of the Cooper pair is also observed for the Fulde Ferrell Larkin Ovchinnikov (FFLO) state previously proposed for periodic systems39,40,41,42. However, the unconventional Cooper pairing in the model QC is completely different from the FFLO state because the Cooper pairing occurs under no magnetic field. In addition, under a high magnetic field, a state similar to the FFLO state is formed in the model QC38. However, this state is also different from the conventional FFLO state in periodic systems and forms a fractal-like spatial pattern of the oscillating superconducting order parameter, which is compatible with the self-similar structural order that is possessed by the QCs. As mentioned above, many interesting features are theoretically expected for superconducting QCs, which are yet to be demonstrated experimentally, and the Ta1.6 Te dodecagonal QC phase in the present study offers a precious platform for it.

In conclusion, polygrain Ta1.6 Te dodecagonal QC samples were fabricated by reaction sintering. Careful phase identification of the sample was performed by electron and powder X-ray diffraction experiments and diffraction-profile simulations. The samples were subjected to electrical resistivity, magnetic susceptibility, and specific heat measurements. The results unconditionally validate the occurrence of bulk superconductivity at a \({T}_{{{{{{\rm{c}}}}}}}\) of ~1 K. This is the first example of superconductivity in thermodynamically stable QCs. These findings are expected to motivate further investigations into the physical properties of vdW layered quasicrystals as well as two-dimensional quasicrystals. In particular, the dodecagonal QC provides a valuable platform for the experimental demonstration of the unique superconductivity theoretically predicted for QCs.

Mar 2, 2024

Complete miscibility of immiscible elements at the nanometre scale

Posted by in categories: materials, nanotechnology

Nanoparticles containing immiscible elements can be synthesized under certain experimental conditions.

Mar 1, 2024

A comprehensive transformer-based approach for high-accuracy gas adsorption predictions in metal-organic frameworks

Posted by in categories: materials, robotics/AI

Furthermore, the experimental values are introduced to correct the adsorption isotherms. For example, Fig. 3b shows the Langmuir adsorption isotherm obtained by fitting both the predicted and experimental adsorption data. While we use simulated datasets to address data scarcity, we can also properly introduce experimental values to correct adsorption isotherms, which helps a more quantitative prediction of adsorption performance at high-pressure where the gas-gas interaction becomes more significant. In Fig. 3b, one can observe that the corrected adsorption isotherms have a strong correlation with experimental adsorption capacity to some extent. The results exhibit that Uni-MOF not only has the ability to screen the adsorption performance of the same gas in different materials but also can accurately screen the adsorption performance of different gases in the same material (Fig. 3c, d) or at different temperatures (Fig. 3e, f).

In the foreseeable future, the intersection of Artificial Intelligence (AI) and materials science will necessitate the resolution of practical and scientific issues. Nonetheless, the attainment of process implementation by AI in the realm of machine learning techniques that entail copious amounts of data remains a formidable challenge, given the dearth of experimental data and the diverse array of synthetic technology and characterization conditions implicated. Our research has made a significant stride in materials science by incorporating operating conditions into the Uni-MOF framework to ensure data adequacy and enable screening functions that are consistent with experimental findings.

In order to showcase the predictive capabilities of Uni-MOF with regard to cross-system properties, five materials were randomly selected from each of the six systems (carbon-dioxide at 298 K, methane at 298 K, krypton at 273 K, xenon at 273 K, nitrogen at 77 K and argon at 87 K) contained in databases hMOF_MOFX_DB and CoRE_MOFX_DB, which have been thoroughly sampled in terms of temperature and pressure. The predicted and simulated values of gas adsorption uptake at varying pressures were then compared, with the results presented in Fig. 4a–f. Adsorption isotherms fitting from both Uni-MOF predictions and simulated values would artificially reduce visual errors. In order to eliminate data bias, adsorption isotherms in all cases were obtained only by simulated values. It is evident that, due to the fact that the adsorption isotherms were obtained purely through simulated values, the predicted values of adsorption uptake generated by Uni-MOF for the hMOF_MOFX_DB and CoRE_MOFX_DB databases align closely with the simulated values across all cases. This finding is further supported by the high prediction accuracy demonstrated in Fig. 2a, b.

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