Unified Interpretations of Two Kinds of Needle-Shaped Precipitates Using Transmission Electron Microscopy and Small-Angle Neutron Scattering in Aged Al-MgSi(-Cu) Alloys.

This study investigates the nanostructural properties of pseudo-binary Al-1.0MgSi (mass%) alloys with and without 0.5Cu using transmission electron microscopy (TEM) and small-angle neutron scattering (SANS).

Polarized Neutrons Observed Nanometer-Thick Crystalline Ice Plates in Frozen Glucose Solution.

Spin-contrast-variation (SCV) small-angle neutron scattering (SANS) is a technique to determine the nanostructure of composite materials from the scattering of polarized neutrons that changes with proton polarization of samples. The SCV-SANS enabled us to determine structure of nanoice crystals that were generated in rapidly frozen sugar solutions by separating the overlapped signals from the nanoice crystals and frozen amorphous solutions. In the frozen glucose solution, we found that the nanoice crystals formed a planar structure with a radius larger than several tens of nanometers and a thickness of 2.

Anomalous behavior of liquid molecules near solid nanoparticles: Novel interpretation on thermal conductivity enhancement in nanofluids.

Hypothesis: Recently, it has been reported that anomalous improvement in the thermal conductivity of nanofluid composed of base liquids and dispersed solid nanoparticles, compared to the theoretically predicted value calculated from the particle fraction. Generally, the thermal conductivity values of gases and liquids are dominated by the mean free path of the molecules during translational motion. Herein, we present solid evidence showing the possible contribution of the vibrational behavior of liquid molecules around nanoparticles to increasing these thermal conductivities.

Square and rhombic lattices of magnetic skyrmions in a centrosymmetric binary compound.

Magnetic skyrmions are topologically stable swirling spin textures with particle-like character, and have been intensively studied as a candidate of high-density information bit. While magnetic skyrmions were originally discovered in noncentrosymmetric systems with Dzyaloshinskii-Moriya interaction, recently a nanometric skyrmion lattice has also been reported for centrosymmetric rare-earth compounds, such as GdPdSi and GdRuSi. For the latter systems, a distinct skyrmion formation mechanism mediated by itinerant electrons has been proposed, and the search of a simpler model system allowing for a better understanding of their intricate magnetic phase diagram is highly demanded.

Above-ordering-temperature large anomalous Hall effect in a triangular-lattice magnetic semiconductor.

While anomalous Hall effect (AHE) has been extensively studied in the past, efforts for realizing large Hall response have been mainly limited within intrinsic mechanism. Lately, however, a theory of extrinsic mechanism has predicted that magnetic scattering by spin cluster can induce large AHE even above magnetic ordering temperature, particularly in magnetic semiconductors with low carrier density, strong exchange coupling, and finite spin chirality. Here, we find out a new magnetic semiconductor EuAs, where Eu ions with large magnetic moments form distorted triangular lattice.

Na Diffusion in Hard Carbon Studied with Positive Muon Spin Rotation and Relaxation.

The diffusive nature of Na in Na-inserted hard carbon (C Na), which is the most common anode material for a Na-ion battery, was studied with a positive muon spin rotation and relaxation (μSR) technique in transverse, zero, and longitudinal magnetic fields (TF, ZF, and LF) at temperatures between 50 and 375 K, where TF (LF) denotes the applied magnetic field perpendicular (parallel) to the initial muon spin polarization. At temperatures above 150 K, TF-μSR measurements showed a distinct motional narrowing behavior, implying that Na begins to diffuse above 150 K. The presence of two different muon sites in C Na was confirmed with ZF- and LF-μSR measurements; one is in the Na-inserted graphene layer, and the other is in the Na-vacant graphene layer adjacent to the Na-inserted graphene layer.

Structural Transition with a Sharp Change in the Electrical Resistivity and Spin-Orbit Mott Insulating State in a Rhenium Oxide, SrReO.

We report the successful synthesis, crystal structure, and electrical properties of SrReO, which contains Re with the 5d configuration. This compound is isostructural with BaReO and shows a first-order structural phase transition at ∼370 K. The low-temperature (LT) phase crystallizes in a hettotype structure of BaReO, which is different from that of the LT phase of SrWO, suggesting that the electronic state of Re plays an important role in determining the crystal structure of the LT phase.

Skyrmion phase and competing magnetic orders on a breathing kagomé lattice.

Magnetic skyrmion textures are realized mainly in non-centrosymmetric, e.g. chiral or polar, magnets.

Neutron scattering studies on short- and long-range layer structures and related dynamics in imidazolium-based ionic liquids.

Alkyl-methyl-imidazolium ionic liquids CnmimX (n: alkyl-carbon number, X: anion) have short-range layer structures consisting of ionic and neutral (alkylchain) domains. To investigate the temperature dependences of the interlayer, interionic group, and inter-alkylchain correlations, we have measured the neutron diffraction (ND) of C16mimPF, C9.5mimPF, and C8mimPF in the temperature region from 4 K to 470 K.

Contrast variation by dynamic nuclear polarization and time-of-flight small-angle neutron scattering. I. Application to industrial multi-component nanocomposites.

Dynamic nuclear polarization (DNP) at low temperature (1.2 K) and high magnetic field (3.3 T) was applied to a contrast variation study in small-angle neutron scattering (SANS) focusing on industrial rubber materials.

Magnetic scattering in the simultaneous measurement of small-angle neutron scattering and Bragg edge transmission from steel.

Pulsed neutron sources enable the simultaneous measurement of small-angle neutron scattering (SANS) and Bragg edge transmission. This simultaneous measurement is useful for microstructural characterization in steel. Since most steels are ferromagnetic, magnetic scattering contributions should be considered in both SANS and Bragg edge transmission analyses.

Measurement of natural carbon isotopic composition of acetone in human urine.

The natural carbon isotopic composition of acetone in urine was measured in healthy subjects using gas chromatography-combustion-isotope ratio mass spectrometry combined with headspace solid-phase microextraction (HS-SPME-GC-C-IRMS). Before applying the technique to a urine sample, we optimized the measurement conditions of HS-SPME-GC-C-IRMS using aqueous solutions of commercial acetone reagents. The optimization enabled us to determine the carbon isotopic compositions within ±0.

Direct Evidence of Confined Water in Room-Temperature Ionic Liquids by Complementary Use of Small-Angle X-ray and Neutron Scattering.

The direct evidence of confined water ("water pocket") inside hydrophilic room-temperature ionic liquids (RTILs) was obtained by complementary use of small-angle X-ray scattering and small-angle neutron scattering (SAXS and SANS). A large contrast in X-ray and neutron scattering cross-section of deuterons was used to distinguish the water pocket from the RTIL. In addition to nanoheterogeneity of pure RTILs, the water pocket formed in the water-rich region.