Hydrogen incorporation in spinel group materials has been extensively investigated. Natural Cr-Al spinel is usually completely anhydrous. We have found euhedral single crystals of hydroxide spinel (3-8 wt%H2O) in a diamond-bearing serpentinite mélange exhumed from depths greater than 90 km. A significant H is incorporated into the spinel structure along with the formation of cation vacancies. The hydroxide spinel can be approximated by (□1-yB3+y) A2+B3+ [O1+3y(OH)3-3y]. The substitution by tetravalent Si or Ti stabilizes the hydroxide spinel structure. The formation of this high configuration-entropy multi-defects hydroxide spinel indicates an abundant supply of hydrogen, therefore must have occurred under water-saturated conditions. The occurrence of the hydroxide spinel provides compelling evidence that the cold subduction plates transport water deep into the mantle, hydrating the transition zone reservoir.

The compositional ranges of SFCA series and the phase equilibrium relationships were reevaluated in the iron-rich corner of the CaO-Fe2O3-Al2O3 system at 1 240 degrees C in air using powder and single crystal XRD as well as EPMA: The liquidus line was reexamined using the samples with initial compositions close to the liquidus line. The observed liquidus line was shifted to the Fe2O3 rich side from the previous one reported by the present authors. The liquidus compositions of the samples, the initial compositions of which were far from the liquidus line, may be affected by CF (CaFe2O4), CFF (Ca2Fe15.51O25) and C2F (Ca2Fe2O5) precipitated during quenching. Some of the limits of compositional range of SFCA-I, SFCA-II and SFCA were determined by newly prepared samples with the three-phase equilibriums such as liquid + SFCA-I + hematite. It has been found that the Al2O3 concentration is the smallest for SFCA-I and the largest for SFCA: The Al/(Al + Ca + Fe) ranges from 5.61% to 17.55% for SFCA-I in equilibrium with a liquid phase, from 14.75% or even lower to 25.00% for SFCA-II and from 19.93% to 31.42% or even higher for SFCA. It has been found that the phases of a sample having the initial composition of 10.04CaO-63.47FeO1.5-26.49AlO1.5 (mol%) equilibrated at the oxygen partial pressure of 0.1 atm and at 1 390 degrees C are SFCA-I and SFCA-III. The value of Fe2+/Fe in SFCA-III has been calculated to be 20.36% assuming that the structural formula of M26O36 (M = Ca, Fe, Al) is satisfied by the presence of Fe2+: (Ca2+1-xFe2+x)6(Fe3+1-yAl3+y)20O36 (x = 0.57, y = 0.33).

Ni-Cu alloy single crystals with lattice constants tailored to match diamond were successfully fabricated using both resistance-heated and induction-heated Czochralski (CZ) methods. Composition design based on Vegard's law and the Ni-Cu phase diagram identified Ni0.477Cu0.523 (at%) as the optimal melt composition ratio to achieve a lattice constant 3.567 & Aring; (lattice constant of diamond). Crystal growth was stabilized along major crystallographic orientations, including (111), and produced a single crystal of up to 82 mm in length and 28 mm in diameter. Structural evaluation indicated excellent crystalline quality, as shown by sharp Laue diffraction patterns obtained at various positions along the ingot. Powder X-ray diffraction performed on sectioned and annealed samples demonstrated lattice constants ranging from 3.559 to 3.563 & Aring;, confirming that the alloy composition reliably approaches the target value for diamond lattice matching. Rocking curve measurements of electrochemically polished Ni-Cu plates yielded a full width at half maximum (FWHM) of 1311 arcsec, providing evidence of the single-crystal nature of the material while also reflecting residual compositional and strainrelated effects inherent to alloy systems. Growth defects such as dendritic structures were interpreted using the framework of constitutional supercooling, and comparisons with Fe-Ga alloy growth highlight the need for steep temperature gradients and controlled pulling rates. The collective results demonstrate that Ni-Cu alloy single crystals represent a promising class of materials for lattice-matched substrates for diamond-based optical and electronic applications.

The structural parameters of penta-chromium triboride, Cr5B3, with Shastry-Sutherland lattices were refined based on single-crystal X-ray diffraction data. Cr5B3 crystallizes in the space group I4/mcm (No. 140), with the following lattice parameters: a = 5.4728 (1) and c = 10.0794 (2) Å. The present study succeeded in refining the positional and anisotropic atomic displacement parameters of the Cr and B atoms.

The three types of superstructures, 1 1 2 , 1 1 1 3 and 1 1 1 4types, exist in the ScRh3B0.75 compound with the Cu3Au/ 1 2 2 3 3 4 4 anti-perovskite type structure. We have used the recently developed 4D-STEM observation with the pixel-type detector to reveal the features of micro- and nanostructures in the ScRh3B0.75 compound. The reconstructed diffraction maps from the 4D-STEM dataset visualized a distribution of micro/nanostructures of the 1 1 2-, 1 1 1 2 2 3 3 3- 1 and 1 1 4-type superstructure domains. Characteristic contrasts in reconstructed dark-field (DF)-scanning trans1 4 4 mission electron microscopy (STEM) images of the 1 1 2-type superstructure domains are similar to those of anti- 1 2 2 phase boundaries in the ordered phase of intermetallic compounds. The 1 1 3 and 1 1 1 4types superstructure 1 3 3 4 4 domains complementary exist. An energy-dispersive X-ray spectroscopy (EDS)-STEM map indicates that the three types of superstructures originate from the ordering of both B atoms and Rh octahedra rather than from the maldistribution of Sc and/or Rh atoms. The locally distorted dark dots in the atomic-resolution annular bright- field (ABF)-STEM image directly suggest that the displacement of Rh atoms around boron atoms occurs three- dimensionally and locally. The superstructure nanodomains of Rh octahedra without boron atoms exist two- dimensionally on the {111} planes in superstructure models induced from the Fourier filtered images of the atomic-resolution STEM image.

This study investigates the influence of synthesis conditions on electrode performance by growing TiNb2O7 (TNO) single crystals, conducting single-crystal X-ray structural analysis, and comparing the resulting structures. The findings revealed that the site preferences of Ti4+ and Nb5+ within the five octahedral sites (M1-M5) remained unaffected by the synthesis atmosphere at low temperatures below 800 degrees C. However, an increase in synthesis temperature from 800 degrees C onwards enhanced the site preference, particularly at the M1 and M5 sites, displaying significant changes. Based on the anisotropy of ion conduction and the conduction mechanism of TNO, it is proposed that ion conduction is facilitated by the positioning of Ti4+ at the M1 site, which is characterized by many shared edges within the tunnel structure and plays a critical role in enabling Li-ion conduction. While the site selectivity of Ti4+ and Nb5+ remained constant across synthesis atmospheres, the observed increase in the lattice constant and electronic conductivity contributed to the charge-discharge characteristics. In contrast, the sample synthesized at 800 degrees C, which exhibited the highest charge-discharge performance among the temperature-varied samples, had the highest occupancy rate of Ti4+ at the M1 site. This occupancy is hypothesized to underpin its superior electrochemical performance.

Single-crystal anomalous X-ray scattering (AXS) experiments were conducted to investigate the cation distribution of calcium-niobium-gallium garnet (CNGG). AXS measurements suggested an ordered distribution of Nb at the octahedral site, and further structural refinement allowed us to obtain the structural formula Ca3Nb1.703(0) Ga3.162(2)O12. Ca was only located in the dodecahedral site, while Ga was distributed in the octa- and tetrahedral sites. The tetrahedral site had a significant number of vacancies at a ratio of one vacancy per unit cell, and the Nb/Ga occupation ratio at the octahedral site results in non-stoichiometric chemical composition of CNGG and its unique broad absorption wavelength. The findings of this study can contribute to device fabrication, property optimization, and quality control processes related to CNGG.

Fluoride crystals with extremely wide band gaps are ideal optical materials in the UV wavelength range. Large 4-inch diameter calcium strontium fluoride (Ca0.582Sr0.418F2) single crystal was grown using the Czochralski method with a Cone-shape Die (CD-CZ). The refractive index and relative transmittance of the crystal was evaluated by cutting it into a triangular prism and polished. The direct measurement of the refractive index and relative transmittance was done by using a spectrograph to image the refraction of light as it passes through a dual prism set-up consisting of a SQ prism as reference and either CaF2 or Ca0.582Sr0.418F2 as the material under evaluation. Characterization results showed that Ca0.582Sr0.418F2 has excellent refractive index dispersion and transmittance in the UV region, confirming the applicability of the dual prism with spectrograph setup to measurements of the refractive index and relative transmittance in the UV region.

Copper (Cu) and other metal single crystals are useful as substrates for the deposition of atomic layer materials for many electronic applications, but the growth of large-sized single crystals is difficult to achieve. Characteristics of the metal material, namely seed elongation and intense cooling radiation at high temperatures during crystal growth, are the main challenges encountered when growing ingots with large diameters. These problems can be resolved by optimizing the crystal growth parameters. By adjusting the shoulder formation angle of the ingot shape to approximately 20 degrees to 40 degrees, we are able to grow a large (1-inch diameter, 30 mm length) single crystal of metal Cu using the Czochralski (CZ) method. However, the generation of suspended solids and film impurities such as reactants and precipitates and their nucleation, growth, and solidification, limited the further increase in size of the Cu crystal. Using the cone-shape die CZ (CD-CZ) method solves this problem and a 2-inch diameter Cu single crystal is successfully grown. This is the world's largest single crystal metal grown using this method and it paves the way for the growth of other metal crystals.

We fabricated porous particles incorporating sugars (mannitol, sucrose, or dextran) and fenofibrate nanoparticles (FNPs) by using spray-freeze-drying (SFD). The type of sugar significantly influenced the pore architecture of the resulting SFD particles. Rapid freezing of droplets containing dextran produced ice encapsulation within a dextran matrix, forming porous dextran particles. In the presence of FNPs, the particle size (approximately 4 μm) and pore volume (0.3 cm3/g) of SFD dextran were barely affected. In contrast, SFD particles derived from mannitol and sucrose exhibited denser structures with a lower pore volume than dextran. SFD mannitol incorporating FNPs produced porous structures. FNPs containing surfactant and polymer, which reduced surface tension and increased viscosity, promoted the formation of small droplets with a polymeric structure and porous particles with a relatively sharp size distribution with a median around 5 μm. FNPs were uniformly distributed in SFD dextran, which featured large pore structures, whereas in SFD mannitol, the Raman signal of FNPs was more broadly distributed across the powder samples. Both morphologies contributed to enhancing the FNP dispersibility within a redispersed suspension of SFD particles. FNPs in SFD mannitol and dextran matrices maintained their particle size distribution from before SFD, showing no aggregation upon redispersion. Dextran formed a highly porous network irrespective of the presence of FNPs, whereas mannitol tended to alter the particle attributes upon FNP inclusion. In conclusion, SFD particles derived from dextran and mannitol might help to increase FNP dispersibility by increasing the formation of porous architectures.

We synthesized a perovskite-type RbNbO3 at 1173 K and 4 GPa from non-perovskite RbNbO3 and investigated its crystal structure and properties towards ferroelectric material design. Single-crystal X-ray diffraction analysis revealed an orthorhombic cell in the perovskite-type structure (space group Amm2, no. 38) with a = 3.9937(2) Å, b = 5.8217(3) Å, and c = 5.8647(2) Å. This non-centrosymmetric space group is the same as the ferroelectric BaTiO3 and KNbO3 but with enhanced distortion. Structural transition from orthorhombic to two successive tetragonal phases (Tetra1 at 493 K, Tetra2 at 573 K) was observed, maintaining the perovskite framework before reverting to the triclinic ambient phase at 693 K, with no structural changes between 4 and 300 K. The first transition is similar to that of KNbO3, whereas the second to Tetra2, marked by c-axis elongation and a significant cp/ap ratio jump (from 1.07 to 1.43), is unique. This distortion suggests a transition similar to that of PbVO3, where an octahedron's oxygen separates along the c-axis, forming a pyramid. Ab initio calculations simulating negative pressure like thermal expansion predicted this phase transition (cp/ap = 1.47 at -1.2 GPa), aligning with experimental findings. Thermal analysis revealed two endothermic peaks, with the second transition entailing a greater enthalpy change and volume alteration. Strong second harmonic generation signals were observed across Ortho, Tetra1, and Tetra2 phases, similar to BaTiO3 and KNbO3. Permittivity increased during the first transition, although the second transition's effects were limited by thermal expansion-induced bulk sample collapse. Perovskite-type RbNbO3 emerges as a promising ferroelectric material.