The asymmetric unit of the title compound, [Fe(C13H18BN6)2], contains two half independent complex mol­ecules. In each complex, the FeII atom is located on an inversion center and is surrounded by two scorpionate ligand butyl­tris­(1H-pyrazol-1-yl)borate mol­ecules that coordinate to the iron(II) ion through the N atoms of the pyrazole groups. The two independent complex mol­ecules differ essentially in the conformation of the butyl substituents. In the crystal, the complex mol­ecules are linked by a series of C—H⋯π inter­actions, which generate a supra­molecular three-dimensional structure. At 120 K, the average Fe—N bond distance is 1.969 Å, indicating the low-spin state of the iron(II) atom, which does not change upon heating, as demonstrated by high-temperature magnetic susceptibility measurements.

Advances in both non-resonant and resonant X-ray magnetic diffraction since the 1980s have provided researchers with a powerful tool for exploring the spin, orbital and ion degrees of freedom in magnetic solids, as well as parsing their interplay. Here, we discuss key issues for performing X-ray magnetic diffraction on single-crystal samples under high pressure (above 40 GPa) and at cryogenic temperatures (4 K). We present case studies of both non-resonant and resonant X-ray magnetic diffraction under pressure for a spin-flip transition in an incommensurate spin-density-wave material and a continuous quantum phase transition of a commensurate all-in–all-out antiferromagnet. Both cases use diamond-anvil-cell technologies at third-generation synchrotron radiation sources. In addition to the exploration of the athermal emergence and evolution of antiferromagnetism discussed here, these techniques can be applied to the study of the pressure evolution of weak charge order such as charge-density waves, antiferro-type orbital order, the charge anisotropic tensor susceptibility and charge superlattices associated with either primary spin order or softened phonons.

Functional materials are of critical importance to electronic and smart devices. A deep understanding of the structure–property relationship is essential for designing new materials. In this work, instead of utilizing conventional atomic coordinates, a symmetry-mode approach is successfully used to conduct structure refinement of the neutron powder diffraction data of (1−x)AgNbO3–xLiTaO3 (0 ≤ x ≤ 0.09) ceramics. This provides rich structural information that not only clarifies the controversial symmetry assigned to pure AgNbO3 but also explains well the detailed structural evolution of (1−x)AgNbO3–xLiTaO3 (0 ≤ x ≤ 0.09) ceramics, and builds a comprehensive and straightforward relationship between structural distortion and electrical properties. It is concluded that there are four relatively large-amplitude major modes that dominate the distorted Pmc21 structure of pure AgNbO3, namely a Λ3 antiferroelectric mode, a T4+ a−a−c0 octahedral tilting mode, an H2 a0a0c+/a0a0c− octahedral tilting mode and a Γ4− ferroelectric mode. The H2 and Λ3 modes become progressively inactive with increasing x and their destabilization is the driving force behind the composition-driven phase transition between the Pmc21 and R3c phases. This structural variation is consistent with the trend observed in the measured temperature-dependent dielectric properties and polarization–electric field (P-E) hysteresis loops. The mode crystallography applied in this study provides a strategy for optimizing related properties by tuning the amplitudes of the corresponding modes in these novel AgNbO3-based (anti)ferroelectric materials.

Meta-magnetic shape-memory alloys combine ferroelastic order with ferromagnetic order and exhibit attractive multifunctional properties, but they are extremely brittle, showing hardly any tensile deformability, which impedes their practical application. Here, for the first time, an Ni–Cu–Co–Mn–In microwire has been developed that simultaneously exhibits a magnetic field-induced first-order meta-magnetic phase transition and huge tensile superelasticity. A temperature-dependent in situ synchrotron high-energy X-ray diffraction investigation reveals that the martensite of this Ni43.7Cu1.5Co5.1Mn36.7In13 microwire shows a monoclinic six-layered modulated structure and the austenite shows a cubic structure. This microwire exhibits an oligocrystalline structure with bamboo grains, which remarkably reduces the strain incompatibility during deformation and martensitic transformation. As a result, huge tensile superelasticity with a recoverable strain of 13% is achieved in the microwire. This huge tensile superelasticity is in agreement with our theoretical calculations based on the crystal structure and lattice correspondence of austenite and martensite and the crystallographic orientation of the grains. Owing to the large magnetization difference between austenite and martensite, a pronounced magnetic field-induced magnetostructural transition is achieved in the microwire, which could give rise to a variety of magnetically driven functional properties. For example, a large magnetocaloric effect with an isothermal entropy change of 12.7 J kg−1 K−1 (under 5 T) is obtained. The realization of magnetic-field- and tensile-stress-induced structural transformations in the microwire may pave the way for exploiting the multifunctional properties under the coupling of magnetic field and stress for applications in miniature multifunctional devices.

The present work reports on the charge and spin density modelling of YTiO3 in its ferromagnetic state (TC = 27 K). Accurate polarized neutron diffraction and high-resolution X-ray diffraction (XRD) experiments were carried out on a single crystal at the ORPHÉE reactor (LLB) and SPRING8 synchrotron source. The experimental data are modelled by the spin resolved pseudo-atomic multipolar model (Deutsch et al., 2012). The refinement strategy is discussed and the result of this electron density modelling is compared with that from XRD measured at 100 K and with density functional theory calculations. The results show that the spin and charge densities around the Ti atom have lobes directed away from the O atoms, confirming the filling of the t2g orbitals of the Ti atom. The dxy orbital is less populated than dxz and dyz, which is a sign of a partial lift of degeneracy of the t2g orbitals. This study confirms the orbital ordering at low temperature (20 K), which is already present in the paramagnetic state above the ferromagnetic transition (100 K).

For Heusler-type Ni–Mn–Ga ferromagnetic shape-memory alloys, the configuration of the martensite variants is a decisive factor in achieving a large magnetic shape-memory effect through field-induced variant reorientation. Based upon the spatially resolved electron backscatter diffraction technique, the microstructural evolution associated with the martensitic transformation from austenite to seven-layered modulated (7M) martensite was investigated on a polycrystalline Ni53Mn22Ga25 alloy. It was clearly shown that grain interior nucleation led to the formation of diamond-shaped 7M martensite within the parent austenite matrix. This diamond microstructure underwent further growth through an isotropic expansion with the coordinated outward movement of four side habit planes, followed by an anisotropic elongation with the forward extension of a type-I twin pair. A two-step growth model is proposed to describe the specific morphology and crystallography of 7M martensite. In addition, the habit planes were revealed to possess a stepped structure, with the {1 0 1}A plane as the terrace and the {0 1 0}A plane as the step. The characteristic combination of martensite variants and the underlying mechanism of self-accommodation in the martensitic transformation have been analysed in terms of the minimum total transformation strain, where the deformation gradient matrix was constructed according to the experimentally determined orientation relationship between the two phases. The present results may deepen the understanding of special martensite microstructures during the martensitic transformation in ferromagnetic shape-memory alloys.

A series of Co2−xRuxMnSi (x = 0, 0.25, 0.5, 0.75, 1) Heusler compounds were successfully synthesized. The heat-treatment conditions were crucial to make the materials form a single phase with a Heusler structure. With increasing Ru content, the half-metallic gap, lattice parameters and magnetization are continuously adjustable in a wide range. The Co2−xRuxMnSi (x = 0, 0.25) compounds are rigorous half-metals and show a T3 dependence of resistance at low temperature. The Co2−xRuxMnSi (x = 0.5, 0.75, 1) Heusler compounds are the nearly half-metallic materials and show a semiconductive dependence of resistance at low temperature. The experimental magnetization is consistent with that in theory and follows the Slater–Pauling rule. The Curie temperature is higher than 750 K for all Co2−xRuxMnSi Heusler compounds.

Small-angle scattering of X-rays and neutrons is a routine method for the determination of nanoparticle sizes. The so-called Guinier law represents the low-q approximation for the small-angle scattering curve from an assembly of particles. The Guinier law has originally been derived for nonmagnetic particle-matrix-type systems and it is successfully employed for the estimation of particle sizes in various scientific domains (e.g. soft-matter physics, biology, colloidal chemistry, materials science). An important prerequisite for it to apply is the presence of a discontinuous interface separating particles and matrix. Here, the Guinier law is introduced for the case of magnetic small-angle neutron scattering and its applicability is experimentally demonstrated for the example of nanocrystalline cobalt. It is well known that the magnetic microstructure of nanocrystalline ferromagnets is highly nonuniform on the nanometre length scale and characterized by a spectrum of continuously varying long-wavelength magnetization fluctuations, i.e. these systems do not manifest sharp interfaces in their magnetization profile. The magnetic Guinier radius depends on the applied magnetic field, on the magnetic interactions (exchange, magnetostatics) and on the magnetic anisotropy-field radius, which characterizes the size over which the magnetic anisotropy field is coherently aligned into the same direction. In contrast to the nonmagnetic conventional Guinier law, the magnetic version can be applied to fully dense random-anisotropy-type ferromagnets.

Methods are presented that detect three types of aberrations in single-particle cryo-EM data sets: symmetrical and antisymmetrical optical aberrations and magnification anisotropy. Because these methods only depend on the availability of a preliminary 3D reconstruction from the data, they can be used to correct for these aberrations for any given cryo-EM data set, a posteriori. Using five publicly available data sets, it is shown that considering these aberrations improves the resolution of the 3D reconstruction when these effects are present. The methods are implemented in version 3.1 of the open-source software package RELION.

A large amount of hydrogen circulates inside the Earth, which affects the long-term evolution of the planet. The majority of this hydrogen is stored in deep Earth within the crystal structures of dense minerals that are thermodynamically stable at high pressures and temperatures. To understand the reason for their stability under such extreme conditions, the chemical bonding geometry and cation exchange mechanism for including hydrogen were analyzed in a representative structure of such minerals (i.e. phase E of dense hydrous magnesium silicate) by using time-of-flight single-crystal neutron Laue diffraction. Phase E has a layered structure belonging to the space group R3m and a very large hydrogen capacity (up to 18% H2O weight fraction). It is stable at pressures of 13–18 GPa and temperatures of up to at least 1573 K. Deuterated high-quality crystals with the chemical formula Mg2.28Si1.32D2.15O6 were synthesized under the relevant high-pressure and high-temperature conditions. The nuclear density distribution obtained by neutron diffraction indicated that the O—D dipoles were directed towards neighboring O2− ions to form strong interlayer hydrogen bonds. This bonding plays a crucial role in stabilizing hydrogen within the mineral structure under such high-pressure and high-temperature conditions. It is considered that cation exchange occurs among Mg2+, D+ and Si4+ within this structure, making the hydrogen capacity flexible.

Researchers at the Smithsonian Conservation Biology Institute conducted three different kinds of genetics tests and all yielded the same result—the Galapagos seabirds have been genetically different from the magnificent frigatebirds elsewhere for more than half a million years.

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A July 12 news alert from NASA indicates a X1.4 class solar flare erupted from the center of the Sun, peaking July 12 at 12:52 P.M.

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Magnetic field measurement techniques have long enabled scientists to probe the internal structure of biological and material samples. For example, magnetic resonance imaging (MRI) provides […]

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Stars form when gravity pulls together material within giant clouds of gas and dust. But gravity isn’t the only force at work. Both turbulence and […]

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Most people think of black holes as giant vacuum cleaners sucking in everything that gets too close. But the supermassive black holes at the centers […]

The post Event Horizon Telescope Reveals Magnetic Fields at Milky Way’s Central Black Hole appeared first on Smithsonian Insider.

Keith Gagnon, a 9-year-old fascinated by birds, talks about the importance of bird conservation and why birds really matter. Step outside your house in the […]

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Using new numerical simulations and observations, scientists may now be able to explain why the Sun’s magnetic field reverses every eleven years. This significant discovery […]

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The Sun glows with a surface temperature of about 5,500 degrees Celsius (9,932 degrees Fahrenheit). On the other hand its hot outer layer, the corona, […]

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The National Museum of Natural History will permanently display the Dom Pedro Aquamarine, which is the largest single piece of cut-gem aquamarine in the world, beginning Dec. 6.

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Nearly four billion years ago, life arose on Earth. Life appeared because our planet had a rocky surface, liquid water, and a blanketing atmosphere. But […]

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Researchers at the Smithsonian's National Zoo's new genetics lab use animal DNA to diagnose new diseases, discover new species help in conservation efforts and solve mysteries.

The post Scientists at a new National Zoo laboratory use DNA to diagnose illnesses and discover new species of animals appeared first on Smithsonian Insider.

During investigations of the formation of hydrated magnesium carbonates, a sample of the previously unknown magnesium carbonate hexa­hydrate (MgCO3·6H2O) was synthesized in an aqueous solution at 273.15 K. The crystal structure consists of edge-linked isolated pairs of Mg(CO3)(H2O)4 octa­hedra and noncoordinating water mol­ecules, and exhibits similarities to NiCO3·5.5H2O (hellyerite). The recorded X-ray diffraction pattern and the Raman spectra confirmed the formation of a new phase and its transformation to magnesium carbonate trihydrate (MgCO3·3H2O) at room temperature.

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Earth's magnetic field seems steady and true -- reliable enough to navigate by. Yet, largely hidden from daily life, the field drifts, waxes and wanes. The magnetic North Pole is currently shifting toward Siberia, forcing the Global Positioning System that underlies modern navigation to update its software sooner than expected. Every several hundred thousand years, the magnetic field dramatically shifts and reverses its polarity. Magnetic north flips to the geographic South Pole and, eventually, back again. This reversal has happened countless times over Earth's history, but scientists' understanding of why and how the field reverses is limited. The researchers find that the most recent field reversal 770,000 years ago took at least 22,000 years to complete, several times longer than previously thought. The results call into question controversial findings that some reversals could occur within a human lifetime.

Image credit: Brad Singer

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National Science Foundation (NSF)-funded researchers from North Carolina State and Elon universities have developed a technique that allows them to remotely control the movement of soft robots, lock them into position for as long as needed and later reconfigure the robots into new shapes. The technique relies on light and magnetic fields. "By engineering the properties of the material, we can control the soft robot's movement remotely; we can get it to hold a given shape; we can then return the robot to its original shape or further modify its movement; and we can do this repeatedly. All of those things are valuable, in terms of this technology's utility in biomedical or aerospace applications," says Joe Tracy, a professor of materials science and engineering at NC State and corresponding author of a paper on the work. In experimental testing, the researchers demonstrated that the soft robots could be used to form "grabbers" for lifting and transporting objects. The soft robots could also be used as cantilevers or folded into "flowers" with petals that bend in different directions. "We are not limited to binary configurations, such as a grabber being either open or closed," says Jessica Liu, first author of the paper and a Ph.D. student at NC State. "We can control the light to ensure that a robot will hold its shape at any point."

Image credit: Jessica A.C. Liu

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome -- commonly referred to as ME/CFS -- is a legitimate, serious, and complex systemic disease that frequently and dramatically limits the activities of affected individuals, says a new report from the Institute of Medicine.

Scientists have produced a list of seafloor characteristics to determine the health status of the ecosystem it supports. These indicators could improve the quality and consistency of marine conservation efforts across Europe, particularly where the impact of human activities is high.

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National Science Foundation (NSF)-funded researchers from North Carolina State and Elon universities have developed a technique that allows them to remotely control the movement of soft robots, lock them into position for as long as needed and later reconfigure the robots into new shapes. The technique relies on light and magnetic fields. "By engineering the properties of the material, we can control the soft robot's movement remotely; we can get it to hold a given shape; we can then return the robot to its original shape or further modify its movement; and we can do this repeatedly. All of those things are valuable, in terms of this technology's utility in biomedical or aerospace applications," says Joe Tracy, a professor of materials science and engineering at NC State and corresponding author of a paper on the work. In experimental testing, the researchers demonstrated that the soft robots could be used to form "grabbers" for lifting and transporting objects. The soft robots could also be used as cantilevers or folded into "flowers" with petals that bend in different directions. "We are not limited to binary configurations, such as a grabber being either open or closed," says Jessica Liu, first author of the paper and a Ph.D. student at NC State. "We can control the light to ensure that a robot will hold its shape at any point."

Image credit: Jessica A.C. Liu

Patients with cancer have heightened risks of unintentional and intentional injuries during the diagnostic process, reveal findings from a large study published by The BMJ today.

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The majestic auroras have captivated humans for thousands of years, but their nature -- the fact that the lights are electromagnetic and respond to solar activity -- was only realized in the last 150 years. Thanks to coordinated multi-satellite observations and a worldwide network of magnetic sensors and cameras, close study of auroras has become possible over recent decades. Yet, auroras continue to mystify, dancing far above the ground to some, thus far, undetected rhythm.

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A recent study has developed a method of diagnosing the environmental condition of wildlife habitats in forest areas. This allows biodiversity conservation to be integrated into the planning and management of the European-wide Natura 2000 nature protection areas.

A new aerial survey is the first to assess the possible impact of a research station in Antarctica on magnetic fields. Estimations indicated that the station generated a magnetic field that extends up to 650 metres from the station with a peak strength of 2800 nanotesla (nT) within 100 metres from the station on the ground. This may have implications for organisms in Antarctica that are negatively affected by magnetic fields but further research is needed to investigate this.

Water pollution by toxic elements is a major economic and environmental concern, and mercury is one of the most poisonous of the elements to be released into the environment by industry. Mercury exposure can cause severe ill health. Efficient, simple and convenient methods to remove mercury from industrial and other waste streams and drinking water are essential. This study successfully trialled a new technique, using magnetised multi-walled carbon nanotubes (MWCNTs), to remove mercury from waste water.

At least two research groups in NTU are working on speeding up the process of identifying infected Covid-19 patients with test kits that can show results in minutes, instead of the current day-long wait for polymerase chain reaction (PCR) test results....

You can get this mineral from many foods, but are you getting what you need? Here are some magnesium deficiency symptoms.

Researchers have created a laser powerful enough to detect minute concentrations of gases in the atmosphere or in your mouth.

Try a bubbly drink with an organic twist.

Researchers have developed a soap made of iron rich salts which could one day safely clean tainted water.

Mercury, named for the Roman messenger of the gods, is the smallest planet in our solar system and the closest to the sun. Check out these amazing images

The Lune can identify that your phone is receiving a call, not from a Bluetooth signal but from the wavelength of the phone’s GSM signal.

Corvettes and Vipers aren't getting stopped by police. It's the much more mild-mannered cars that attract attention.

The use-at-home device that treats migraines with a pulse of magnetic energy has shown significant promise in clinical trials.

Ditch the plastic letters and kitschy tourist magnets for something more in touch with nature for your fridge.

Moose lasagna, a hot seller at European stores operated by the world-dominating purveyor of flat-pack furnishings, is found to contain trace amounts of pork.

･ First introduction for a geothermal power plant ･ Enhancing the operation and performance of power generating facilities in close cooperation with customers

The Palo Alto Baylands Preserve is a special place in the San Francisco Bay area of California.

The magnetic pole is moving faster than at any time in human history, causing major problems for navigation and migratory wildlife.