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By using a high-pressure reaction, we prepared a new oxynitride ZnTaO2N that crystallizes in a centrosymmetric (R (3) over barc) high-temperature LiNbO3-type structure (HTLN-type). The stabilization of the HTLN-type structure down to low temperatures (at least 20 K) makes it possible to investigate not only the stability of this phase, but also the phase transition to a noncentrosymmetric (R3c) LiNbO3-type structure (LN-type) which is yet to be clarified. Synchrotron and neutron diffraction studies in combination with transmission electron microscopy show that Zn is located at a disordered 12c site instead of 6a, implying an order disorder mechanism of the phase transition. It is found that the dosed d-shell of Zn2+, as well as the high-valent Ta5+ ion, is responsible for the stabilization of the HTLN-type structure, affording a novel quasitriangular ZnO2N coordination. Interestingly, only 3% Zn substitution for MnTaO2N induces a phase transition from LN- to HTLN-type structure, implying the proximity in energy between the two structural types, which is supported by the first-principles calculations.

The NiAs-type structure is one of the most common structures in solids, but metal order has been almost exclusively limited to chalcogenides. The synthesis of HfMnSb2 is reported with a novel metal-ordered NiAs-type structure. HfMnSb2 undergoes a conical spin order below 270 K, in marked contrast to conventional magnetic order observed in NiAs-type pnictides. We argue that the layered arrangement of Hf and Mn makes it a quasi 2D magnet, where the Mn layers with localized magnetic moments (Mn(2+) ; S=5/2) can interact only through RKKY interactions, instead of metal-metal bonding that is otherwise dominant for typical NiAs-type pnictides. This result suggests that controlling order-disorder in NiAs-type pnictides enables a study of 2D-to-3D crossover behavior in itinerant magnetic system.

In this study, the effects of fabrication conditions on the microstructure, pore characteristics and gas retention of pure tungsten specimens prepared by laser powder bed fusion (LPBF) were investigated. The LPBF specimens contained micro- and nano- sized pores as internal defects. By optimizing the laser irradiation conditions, the formation of micropores was suppressed. The densest LPBF specimen was obtained when the input energy density was adjusted to be 411 J/mm3, and the relative density of the specimen measured by utilizing Archimedes' principle reached 98.58 ± 0.25% (19.03 ± 0.05 g/cm3). Heat treatment at a high temperature (1900 °C) was effective to reduce the number density of nanopores. The compositions and amounts of internal gas in the specimens were examined using a quadrupole mass spectrometer. The results indicated that the specimens contained the argon (Ar), which was used as the shielding gas. The Ar retention was correlated with the number density of nanopores in the specimens and not with the density of micropores. The Ar retention decreased to almost half that in the as-fabricated specimen after the heat treatment at 1900 °C. These observations suggest that Ar gas was trapped in nanopores in the LPBF material. It was demonstrated that a part of the trapped Ar dissolved and diffused in grains during the heat treatment and was released to the outside.

We investigated the structural and optical properties of (A0.6X)Bi4(Nb0.6W0.4)O8X (A = K, Rb, Cs and X = Cl, Br). We found that these Sillen–Aurivillius-related oxyhalides have band gaps of ca. 3.1 eV (X = Cl) and ca. 2.8 eV (X = Br), which are surprisingly larger than 2.4 eV for the archetypal Bi4NbO8Cl, meaning a substantial stabilization of O-2p orbitals upon A0.6X layer insertion. The present study suggests versatile possibilities of band gap engineering in Sillen–Aurivillius type compounds.

Perovskite oxides can host various anion-vacancy orders, which greatly change their properties, but the order pattern is still difficult to manipulate. Separately, lattice strain between thin film oxides and a substrate induces improved functions and novel states of matter, while little attention has been paid to changes in chemical composition. Here we combine these two aspects to achieve strain-induced creation and switching of anion-vacancy patterns in perovskite films. Epitaxial SrVO3 films are topochemically converted to anion-deficient oxynitrides by ammonia treatment, where the direction or periodicity of defect planes is altered depending on the substrate employed, unlike the known change in crystal orientation. First-principles calculations verified its biaxial strain effect. Like oxide heterostructures, the oxynitride has a superlattice of insulating and metallic blocks. Given the abundance of perovskite families, this study provides new opportunities to design superlattices by chemically modifying simple perovskite oxides with tunable anion-vacancy patterns through epitaxial lattice strain., Using strain to control oxynitride properties. 京都大学プレスリリース. 2020-12-01., 原子空孔の配列を制御する新手法の発見. 京都大学プレスリリース. 2020-12-02.

We report the adiabatic temperature change in ErAl2 magnetocaloric wires fabricated by a powder-in-tube (PIT) process. The adiabatic temperature change of the PIT wires is found to be determined by not only the volume fraction of ErAl2 core but also the magnitude relationship between the specific heat of the ErAl2 core and the metal sheath. We propose a quantitative analysis method for calculating the temperature and core volume fraction dependence of adiabatic temperature change in the PIT wire, whose formula is applicable to also various magnetocaloric composites, useful to estimate the magnetocaloric response prior to fabrication., Comment: 14 pages, 5 figures

The Earth’s mantle is characterized by a sharp seismic discontinuity at a depth of 660 km that can provide insights into deep mantle processes. The discontinuity occurs over only 2 km—or a pressure difference of 0.1 GPa—and is thought to result from the post-spinel transition, that is, the decomposition of the mineral ringwoodite to bridgmanite plus ferropericlase. Existing high-pressure, high-temperature experiments have lacked the pressure control required to test whether such sharpness is the result of isochemical phase relations or chemically distinct upper and lower mantle domains. Here, we obtain the isothermal pressure interval of the Mg–Fe binary post-spinel transition by applying advanced multi-anvil techniques with in situ X-ray diffraction with the help of Mg–Fe partition experiments. It is demonstrated that the interval at mantle compositions and temperatures is only 0.01 GPa, corresponding to 250 m. This interval is indistinguishable from zero at seismic frequencies. These results can explain the discontinuity sharpness and provide new support for whole-mantle convection in a chemically homogeneous mantle. The present work suggests that distribution of adiabatic vertical flows between the upper and lower mantles can be mapped on the basis of discontinuity sharpness. The post-spinel transition in mantle composition, which occurs at 660-km depth in Earth’s mantle, takes place over a pressure range equivalent to 250 m in depth, according to multi-anvil experiments for realistic mantle compositions and temperatures.

We have prepared a set of polycrystalline samples of La 0.8 Sr 0.2 Co 1 &minus, x Al x O 3 ( 0 &le, x &le, 0.2 ), and have measured the magnetization as functions of temperature and magnetic field. We find that the average spin number per Co ion ( S Co ) evaluated from the room-temperature susceptibility is around 1.2&ndash, 1.3 and independent of x. However, we further find that S Co evaluated from the saturation magnetization at 2 K is around 0.3&ndash, 0.7, and decreases dramatically with x. This naturally indicates that a significant fraction of the Co 3 + ions experience a spin-state crossover from the intermediate- to low-spin state with decreasing temperature in the Al-substituted samples. This spin-state crossover also explains the resistivity and the thermopower consistently. In particular, we find that the thermopower is anomalously enhanced by the Al substitution, which can be consistently explained in terms of an extended Heikes formula.

We achieve the introduction of an extremly large amount of interstitial hydrogen into strontium titanate (SrTiO

Risk perception and individual reactions to risk are not necessarily comparable, and socioeconomic status may affect individual reactions to risk. This study aimed to investigate the association between socioeconomic status and reactions to radiation exposure risk. This cross-sectional study, based on a self-reported online survey was conducted between 3 March and 21 March 2012, one year after the accident at Fukushima Daiichi nuclear power station. We used feelings of anxiety and risk-averse behavior concerning radiation exposure as dependent variables, and equivalent income and educational attainment as independent variables. Multiple logistic regression analysis was applied to estimate adjusted odds ratios (aORs) and 95% confidence intervals (95% CIs) with adjustment for possible confounders. Among 10 000 participants, 23.0% felt anxious and 12.0% engaged in risk-averse behavior for radiation exposure. Participants with a higher socioeconomic status tended not to feel anxious but undertook risk-averse behavior. Participants in the highest quartile income category did not report feeling anxious but showed prevalent undertaking of risk-averse behavior for radiation exposure compared to the lowest income category (for anxiety, aOR, 0.77; 95% CI, 0.64–0.93, for risk-averse behavior, aOR, 1.33; 95% CI, 1.04–1.69). University or graduate-school graduates were associated with greater risk-averse behavior compared to junior high school or high school graduates (aOR, 1.49; 95% CI, 1.29–1.73). Socioeconomic status may affect reactions to radiation exposure risk. Risk communication strategies should consider the socioeconomic status of those affected.

To estimate quantitatively whether the presence of cough associated with dysphagia (laryngeal cough reflex) increased mortality through respiratory disease among community-dwelling older Japanese.A 6-year follow-up prospective cohort study (from 2010 to 2017).Thirteen municipalities in Japan.Community-dwelling individuals aged 65 years or older (N = 32,682).The baseline survey was conducted through self-reported questionnaire. Exposure was experience of laryngeal cough reflex while drinking. The outcome was all-cause mortality. All covariates were selected from demographic, socioeconomic variables, baseline health and functional status, smoking, alcohol drinking, number of remaining teeth, and stroke. The mediator variable was respiratory disease. Cox proportional hazards regression was used to estimate hazard ratios (HRs) for mortality. Parametric mediation analysis was conducted to estimate the effect of laryngeal cough reflex on the mean residual time to death mediated through respiratory disease.Among the 32,682 participants (mean age = 74.1 years, standard deviation = 5.9 years), 5550 (17.0%) experienced laryngeal cough reflex at baseline. A total of 4037 deaths occurred. Crude mortality rates of the participants with or without laryngeal cough reflex were 16.3% and 11.6%, respectively. After adjusting for covariates, laryngeal cough reflex [HR = 1.10; 95% confidence interval (CI) = 1.02 to 1.19] and respiratory disease (HR = 1.80; 95% CI = 1.62 to 2.00) were associated with mortality. The mediation analysis showed that respiratory disease significantly (P .001) and partially mediated the association between laryngeal cough reflex, an indicator of 1 or more conditions such as chronic aspiration and mortality.Laryngeal cough reflex was a prevalent condition, and it was associated with all-cause mortality in community-dwelling older Japanese individuals. Clinicians could contribute to reduce mortality risk by addressing swallowing function problems using their interprofessional collaboration team (speech-language pathologist, dentist, rehabilitation doctor, otolaryngologist, respiratory physician, and gerontologist).

Square-planar coordinate Ni(2+) ions in oxides are exclusively limited to a low-spin state (S = 0) owing to extensive crystal field splitting. Layered oxychalcogenides A(2)Ni(II)O(2)Ag(2)Se(2) (A = Sr, Ba) with the S = 1 NiO(2) square lattice are now reported. The structural analysis revealed that the Ni(2+) ion is under-bonded by a significant tensile strain from neighboring Ag(2)Se(2) layers, leading to the reduction in crystal field splitting. Ba(2)NiO(2)Ag(2)Se(2) exhibits a G-type spin order at 130 K, indicating fairly strong in-plane interactions. The high-pressure synthesis employed here possibly assists the expansion of NiO(2) square lattice by taking the advantage of the difference in compressibility in oxide and selenide layers.

We synthesized a silver iron oxyfluoride AgFeOF

The relation between metal order-disorder and magnetic properties in the solid solution Hf1–xTixMnSb2 (0 ≤ x ≤ 1) with the NiAs structure is investigated. The synchrotron X-ray diffraction studies have revealed that two-dimensional (2D) metal-ordered structure in HfMnSb2 persists up to x = 0.15, though its degree of metal order decreases with x. Although the NiAs-like phase is not formed for 0.2 ≤ x ≤ 0.3, a metal disordered phase appears for x ≥ 0.4. A conical spin order is only found in the metal-ordered region and is fairly robust against partial cation disorder, while the completely metal-disordered region is a ferromagnetic state, providing firm evidence that the presence/absence of metal order essentially defines the ground state. Neutron depolarization measurement for HfMnSb2 suggests possible successive phase transitions.

Deformational, metamorphic, monazite age and fabric data from Rengali Province, eastern India converge towards a multi-scale transpressional deformational episode at ca. 498–521 Ma which is linked with the latest phase of tectonic processes operative at proto-India-Antarctica join. Detailed sector wise study on mutual overprinting relationships of macro-to microstructural elements suggest that deformation was regionally partitioned into fold-thrust dominated shortening zones alternating with zones of dominant transcurrent deformation bounded between the thrust sense Barkot Shear Zone in the north and the dextral Kerajang Fault Zone in the south. The strain partitioned zones are further restricted between two regional transverse shear zones, the sinistral Riamol Shear Zone in the west and the dextral Akul Fault Zone in the east which are interpreted as synthetic R and antithetic R' Riedel shear plane, respectively. The overall structural disposition has been interpreted as a positive flower structure bounded between the longitudinal and transverse faults with vertical extrusion and symmetric juxtaposition of mid-crustal amphibolite grade basement gneisses over low-grade upper crustal rocks emanating from the central axis of the transpressional belt.

The fluorite-like [Bi2O2](2+) layer is a fundamental building unit in a great variety of layered compounds. Here in this contribution, we presented a comprehensive study on an unusual Aurivillius phase Bi3.6V2O10 with respect to its defect chemistry and polymorphism control as well as implications for fast oxide ion transport at lower temperatures. The bismuth oxide layer in Bi4V2O11 is found to tolerate a large number of Bi vacancies without breaking the high temperature prototype I4/mmm structure (γ-phase). On cooling, an orthorhombic distortion occurs to the γ-phase, giving rise to a different type of phase (B-phase) in the intermediate temperature region. Cooling to room temperature causes a further transition to an oxygen-vacancy ordered A-phase, which is accompanied by the charge ordering of V(4+) and V(5+) cations, providing magnetic (d(1)) and nonmagnetic (d(0)) chains along the a axis. This is a novel charge ordering transition in terms of the concomitant change of oxygen coordination. Interestingly, upon quenching, both the γ- and B-phase can be kinetically trapped, enabling the structural probing of the two phases at ambient temperature. Driven by the thermodynamic forces, the oxide anion in the γ-phase undergoes an interlayer diffusion process to reshuffle the compositions of both Bi-O and V-O layers.

We have studied electronic properties of perovskite oxyhydrides ATiO3–xHx (A = Ba, Sr). Epitaxial thin films of ATiO3–xHx with various hydride compositions, up to x = 0.58 for Ba and x = 0.45 for Sr, are prepared by the low-temperature CaH2 reduction of the corresponding oxide films deposited on (LaAlO3)0.3(SrAl0.5Ta0.5O3)0.7 (LSAT) substrates by pulsed laser deposition. Resistivity measurements for A = Sr show a metallic phase over a wide range of H– composition, implying a substantial stabilization of H 1s orbitals that should be distributed over O 2p orbitals. On the other hand, for A = Ba, a semiconducting behavior is seen up to ∼5–8% of H– substitution. Interestingly, a similar contrasting behavior is observed in a Nb-substituted BaTiO3 and SrTiO3, which suggests that a local cation–off centering in lightly doped Ba films creates in-gap states in the band structure (as opposed to the Sr films), hindering the electron transport.

Scientific reports 8(1), 6358 (2018). doi:10.1038/s41598-018-24832-y, The 660-km seismic discontinuity, which is a significant structure in the Earth’s mantle, is generally interpreted as the post-spinel transition, as indicated by the decomposition of ringwoodite to bridgmanite + ferropericlase. All precise high-pressure and high-temperature experiments nevertheless report 0.5–2 GPa lower transition pressures than those expected at the discontinuity depth (i.e. 23.4 GPa). These results are inconsistent with the post-spinel transition hypothesis and, therefore, do not support widely accepted models of mantle composition such as the pyrolite and CI chondrite models. Here, we present new experimental data showing post-spinel transition pressures in complete agreement with the 660-km discontinuity depth obtained by high-resolution in situ X-ray diffraction in a large-volume high-pressure apparatus with a tightly controlled sample pressure. These data affirm the applicability of the prevailing mantle models. We infer that the apparently lower pressures reported by previous studies are experimental artefacts due to the pressure drop upon heating. The present results indicate the necessity of reinvestigating the position of mantle mineral phase boundaries previously obtained by in situ X-ray diffraction in high-pressure–temperature apparatuses., Published by Springer Nature, Cham

We have prepared the oxyhydride perovskite EuTiO(3-x)H(x) (x ≤ 0.3) by a low temperature CaH2 reduction of pyrochlore Eu2Ti2O7 and perovskite EuTiO3. The reduced EuTiO(3-x)H(x) crystallizes in the ideal cubic perovskite (Pm3̅m), where O/H anions are randomly distributed. As a result of electron doping by the aliovalent anion exchange, the resistivity of EuTiO(3-x)H(x) shows metallic temperature dependence. Moreover, an antiferromagnetic-to-ferromagnetic transition is observed even when a small amount of hydride (x ∼ 0.07) is introduced. The Curie temperature TC of 12 K is higher than those of any other EuTiO3-derived ferromagnets. The ferromagnetism can be explained by the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction between the Eu(2+) spins mediated by the itinerant Ti 3d electrons. The present study shows that controlling the oxide/hydride ratio is a versatile method to tune magnetic and transport properties.

We investigated topochemical anion exchange reactions for a Sc

The synthesis, structure, and magnetic properties of a polar and magnetic oxynitride MnTaO2N are reported. High-pressure synthesis at 6 GPa and 1400 °C allows for the stabilization of a high-density structure containing middle-to-late transition metals. Synchrotron X-ray and neutron diffraction studies revealed that MnTaO2N adopts the LiNbO3-type structure, with a random distribution of O(2-) and N(3-) anions. MnTaO2N with an "orbital-inactive" Mn(2+) ion (d(5); S=5/2) exhibits a nontrivial helical spin order at 25 K with a propagation vector of [0,0,δ] (δ≈0.3), which is different from the conventional G-type order observed in other orbital-inactive perovskite oxides and LiNbO3-type oxides. This result suggests the presence of strong frustration because of the heavily tilted MnO4N2 octahedral network combined with the mixed O(2-)/N(3-) species that results in a distribution of (super)-superexchange interactions.

The hydride reduction of a tetragonal layered perovskite LaSrCoO4 is known to yield orthorhombic LaSrCoO3H0.7 with a complete hydride/oxide order within the ab plane. In this study, epitaxial thin films of LaSrCoO4 with a-axis and c-axis orientations have been deposited on (100) and (001) LaSrAlO4 (LSAO) substrates, respectively, and allowed to react with hydride to convert into oxyhydrides. X-ray diffraction, secondary ion mass spectroscopy and thermal desorption spectroscopy experiments indicate that both films are topochemically reduced and can integrate hydride ions with a chemical composition close to that obtained for the powder. A significant reduction in the a-axis was observed for the a-axis oriented LaSrCoO3H0.7 film, indicating hydride/oxide order, as previously reported. In contrast, the c-axis oriented LaSrCoO3H0.7 film remains tetragonal, suggesting hydride/oxide disorder. These results demonstrate that strain engineering can lead to new materials with designed anion arrangement in mixed anion materials.

Macrophage infiltration in the adipose tissue, and the interaction with adipocytes, is well documented to be involved in fat inflammation and obesity-associated complications. In this study, we isolated IκB kinase ε (IKKε) as a key adipocyte factor that is potentially affected by interaction with macrophages in adipose tissue in vivo. We showed that IKKε mRNA expression levels in white adipose tissue were increased in both genetic and diet-induced obese mouse. Furthermore, IKKε mRNA expression was decreased by the administration of vitamin B6, an anti-inflammatory vitamin, and that IKKε expression levels in adipose tissue were closely correlated with the numbers of infiltrating macrophages. In a co-culture system, we showed that IKKε expression in adipocytes was upregulated by interaction with activated macrophages. This study provides novel insight into IKKε, which is involved in adipose tissue inflammation during the development of obesity.

The superconducting properties of LaPd 2 As 2 with a collapsed tetragonal structure are reported. DC magnetization and resistivity measurements reveal that the compound is a type-II bulk superconductor below 1 K. The electronic specific heat coefficient γ is found to be 5.56 mJ mol − 1 K − 2 . The specific heat change at the superconducting transition is 1.17, which is relatively low compared to the BCS weak coupling limit of 1.43. The density of states at the Fermi level calculated from electronic specific heat data is about 0.84 states/(eV f.u.), which may explain the low T c of this material. These results, together with previous work on A 2+ M 2 X 2 compounds, imply that the superconducting transition temperature can be tailored by proper chemical substitution.

Alkali and alkali earth hydrides have been used as solid state reductants recently to yield many interesting new oxygen-deficient transition metal oxides. These reactions have tacitly been assumed to be a solid phase reaction between the reductant and parent oxide. We have conducted a number of experiments with physical separation between the reductant and oxides, and find that in some cases reduction proceeds even when the reagents are physically separated, implying reactions with in-situ generated H{sub 2} and, to a lesser extent, getter mechanisms. Our findings change our understanding of these topochemical reactions, and should enhance the synthesis of additional new oxides and nanostructures. - Graphical abstract: Topochemical reductions with hydrides: Solid state or gas phase reaction? Display Omitted - Highlights: • SrFeO{sub 2} and LaNiO{sub 2} were prepared by topochemical reduction of oxides. • Separating the reducing agent (CaH{sub 2}, Mg metal) from the oxide still results in reduction. • Such topochemical reactions can occur in the gas phase.

Pressure–composition curves of ZrMn x ( x =1.9, 2.0)-Q 2 (Q=H, D) were measured by a volumetric method. An inverse isotope effect of absorption pressure was found for the ZrMn x Q y system, i.e. the hydrogen absorption pressure was found to be larger than that of deuterium. On the other hand, the hydrogen desorption pressure was the same as that of deuterium. Thus, an inverse isotope effect merely appears in the absorption pressures. The degree of the inverse isotope effect decreased with increasing temperature. This effect can be explained by the hysteresis factor which is induced by hydrogen isotopes dissolved in ZrMn 1.9 or ZrMn 2.0 .

Low-temperature reactions are a powerful approach to generate new transition metal oxides that are inaccessible by conventional high-temperature reactions. In this review, we describe the recent pr...

A previously unreported Pb-based perovskite PbMoO$_3$ is obtained by high-pressure and high-temperature synthesis. This material crystallizes in the $Pm\bar{3}m$ cubic structure at room temperature, making it distinct from typical Pb-based perovskite oxides with a structural distortion. PbMoO$_3$ exhibits a metallic behavior down to 0.1 K with an unusual $T$-sub linear dependence of the electrical resistivity. Moreover, a large specific heat is observed at low temperatures accompanied by a peak in $C_P/T^3$ around 10 K, in marked contrast to the isostructural metallic system SrMoO$_3$. These transport and thermal properties for PbMoO$_3$, taking into account anomalously large Pb atomic displacements detected through diffraction experiments, are attributed to a low-energy vibrational mode, associated with incoherent off-centering of lone pair Pb$^{2+}$ cations. We discuss the unusual behavior of the electrical resistivity in terms of a polaron-like conduction, mediated by the strong coupling between conduction electrons and optical phonons of the local low-energy vibrational mode., Comment: 5 pages, 5 figures

By using a high-pressure reaction, we prepared a new oxynitride ZnTaO

The mantle transition zone contains 1 to 2 weight % water based on the viscosity difference between ringwoodite and bridgmanite., An open question for solid-earth scientists is the amount of water in Earth’s interior. The uppermost mantle and lower mantle contain little water because their dominant minerals, olivine and bridgmanite, have limited water storage capacity. In contrast, the mantle transition zone (MTZ) at a depth of 410 to 660 km is considered to be a potential water reservoir because its dominant minerals, wadsleyite and ringwoodite, can contain large amounts of water [up to 3 weight % (wt %)]. However, the actual amount of water in the MTZ is unknown. Given that water incorporated into mantle minerals can lower their viscosity, we evaluate the water content of the MTZ by measuring dislocation mobility, a property that is inversely proportional to viscosity, as a function of temperature and water content in ringwoodite and bridgmanite. We find that dislocation mobility in bridgmanite is faster by two orders of magnitude than in anhydrous ringwoodite but 1.5 orders of magnitude slower than in water-saturated ringwoodite. To fit the observed mantle viscosity profiles, ringwoodite in the MTZ should contain 1 to 2 wt % water. The MTZ should thus be nearly water-saturated globally.

Using a high-pressure reaction, we successfully synthesized $\mathrm{BaF}{\mathrm{e}}_{2}\mathrm{S}{\mathrm{e}}_{2}\mathrm{O}$ with a uniform stack of $[\mathrm{F}{\mathrm{e}}_{2}\mathrm{S}{\mathrm{e}}_{2}\mathrm{O}]$ layers. Magnetic susceptibility, heat capacity, M\"ossbauer spectroscopy, and neutron-diffraction measurements revealed that $\mathrm{BaF}{\mathrm{e}}_{2}\mathrm{S}{\mathrm{e}}_{2}\mathrm{O}$ undergoes antiferromagnetic order at 106 K with a 2-$k$ spin structure where each Fe moment points to a neighboring oxide anion. The same spin structure has been observed in the related iron oxyselenides but with a staggered stack of $[\mathrm{F}{\mathrm{e}}_{2}\mathrm{C}{\mathrm{h}}_{2}\mathrm{O}]$ (where Ch represents chalcogen) layers $(\mathrm{Ch}\phantom{\rule{0.16em}{0ex}}=\phantom{\rule{0.16em}{0ex}}\mathrm{S},\mathrm{Se})$. We propose that the strong uniaxial anisotropy inferred from the 2-$k$ structure originates from spin-orbit coupling (SOC) induced by a $\mathit{trans}\ensuremath{-}\mathrm{Fe}{\mathrm{O}}_{2}\mathrm{S}{\mathrm{e}}_{4}$ octahedron, which provides a quasilinear coordination environment as often found in single molecule magnetic complexes. A first-principles calculation with inclusion of SOC supports the stabilization of the 2-$k$ spin structure, giving an unquenched orbital momentum of $0.1\phantom{\rule{0.16em}{0ex}}{\ensuremath{\mu}}_{\mathrm{B}}/\mathrm{Fe}$. The present paper provides an idea of how to design magnetic lattices of uniaxial anisotropy using oxychalcogenides and more generally mixed-anion compounds.

HfMnSb2 is synthesized by solid state reaction of stoichiometric mixtures of the elements (pressed pellet, evacuated quartz tube, 800 °C, 48 h).

The high-pressure synthesis of a manganese oxyhydride LaSrMnO3.3 H0.7 is reported. Neutron and X-ray Rietveld analyses showed that this compound adopts the K2 NiF4 structure with hydride ions positioned exclusively at the equatorial site. This result makes a striking contrast to topochemical reductions of LaSrMnO4 that result in only oxygen-deficient phases down to LaSrMnO3.5 . This suggests that high H2 pressure plays a key role in stabilizing the oxyhydride phase, offering an opportunity to synthesize other transition-metal oxyhydrides. Magnetic susceptibility revealed a spin-glass transition at 24 K that is due to competing ferromagnetic (Mn(2+) -Mn(3+) ) and antiferromagnetic (Mn(2+) -Mn(2) , Mn(3+) -Mn(3+) ) interactions.

We will present the synthesis, structure and magnetic properties of a new quadruple-layered perovskite (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13}. Through a topotactic ion-exchange reaction with CuCl{sub 2}, the precursor RbCa{sub 2}NaNb{sub 4}O{sub 13} presumably having an incoherent octahederal tliting changes into (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13} with a 2a{sub p} Multiplication-Sign 2a{sub p} Multiplication-Sign 2c{sub p} superstructure (tetragonal; a=7.73232(5) A, c=39.2156(4) A). The well-defined superstructure for the ion-exchanged product should be stabilized by the inserted CuCl{sub 4}O{sub 2} octahedral layers that firmly connect with neighboring perovskite layers. Magnetic studies show the absence of long-range magnetic ordering down to 2 K despite strong in-plane interactions. Aleksandrov Prime s group theory and Rietveld refinement of synchrotron X-ray diffraction data suggest the structure to be of I4/mmm space group with in-phase tilting along the a and b axes, a two-tilt system (++0). - Graphical Abstract: We present a quadruple-layered copper oxyhalide (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13} synthesized through a topotactic ion-exchange reaction of RbCa{sub 2}NaNb{sub 4}O{sub 13} with CuCl{sub 2}. The compound has a well-defined superstructure. Magnetic studies suggest the absence of magnetic order even at 2 K. Highlights: Black-Right-Pointing-Pointer (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13} was prepared by ion-exchange reaction of RbCa{sub 2}NaNb{sub 4}O{sub 13} with CuCl{submore » 2}. Black-Right-Pointing-Pointer Compound has a 2a{sub p} Multiplication-Sign 2a{sub p} Multiplication-Sign 2c{sub p} superstructure (tetragonal; a=7.73 A, c=39.21 A). Black-Right-Pointing-Pointer Such a well-defined superstructure was not observed in the precursor compound. Black-Right-Pointing-Pointer Aleksandrov Prime s theory and Rietveld study suggest a (++0) octahedral tilting (I4/mmm). Black-Right-Pointing-Pointer Magnetic studies revealed the absence of magnetic order down to 2 K.« less

The rock salt (B1) structure of binary oxides or chalcogenides transforms to the CsCl (B2) structure under high pressure, with critical pressures P(s) depending on the cation to anion size ratio (R(c)/R(a)). We investigated structural changes of A(2)MO(3) (A = Sr, Ca; M = Cu, Pd) comprising alternate 7-fold B1 AO blocks and corner-shared MO(2) square-planar chains under pressure. All of the examined compounds exhibit a structural transition at P(s) = 29-41 GPa involving a change in the A-site geometry to an 8-fold B2 coordination. This observation demonstrates, together with the high pressure study on the structurally related Sr(3)Fe(2)O(5), that the B1-to-B2 transition generally occurs in these intergrowth structures. An empirical relation of P(s) and the R(c)/R(a) ratio for the binary system holds well for the intergrowth structure also, which means that P(s) is predominantly determined by the rock salt blocks. However, a large deviation from the relation is found in LaSrNiO(3.4), where oxygen atoms partially occupy the apical site of the MO(4) square plane. We predict furthermore the occurrence of the same structural transition for Ruddlesden-Popper-type layered perovskite oxides (AO)(AMO(3))(n), under higher pressures. For investigating the effect on the physical properties, an electrical resistivity of Sr(2)CuO(3) is studied.

Skeletal siloxane bonding structure of nanocrystalline MEL pure silica zeolite film was investigated. Nanocrystalline zeolite (nc-zeolite) suspension was prepared by the two-stage hydrothermal treatment, and thin film was obtained by spin-coating. After a quantitative analysis of Fourier-transform infrared spectra with the variable incidence angles of light probe, skeletal complex dielectric function concerning the siloxane bond vibration was derived in the 1400–400 cm–1 range. Then, the widening of the AS1-(LO-TO) frequency splitting width and the enhancement of the normalized integrated oscillator strength of AS vibration mode were observed in the nc-zeolite film in comparison with those of sol–gel derived amorphous silica film. Those improvements must be attributed to the increased siloxane network connectivity and the crystal structure of zeolite. The effect of the UV assist anneal was also discussed.

We have investigated the dilute magnetic impurity effect on the magnetic properties of a quantum spin liquid candidate Ba3ZnRu2O9 and a spin gapped compound Ba3CaRu2O9. The magnetic ground state of each compound stands against 2% substitution of magnetic impurities for Zn or Ca. We have found that the magnetic response of these impurities, which behave as paramagnetic spins, depends on the host materials and the difference of the two manifests itself in the Weiss temperature, which can hardly be explained by the dilute magnetic impurities alone in the case of Ba3ZnRu2O9. We consider a contribution from the Ru5+ ions which would appear only in the substituted Ba3ZnRu2O9 and discuss a possible physical meaning of the observed Weiss temperature., Comment: 10 pages, 4 figures

今回，主膵管内へ進展を呈した膵漿液性嚢胞腺腫の1例を経験した．症例は82歳，男性．前医にて急性膵炎の精査中に膵頭部に充実性腫瘍を指摘され，精査目的にて紹介となった．腫瘍は約2cm大で，造影CT早期相で造影効果を示し，後期相でwash outした．CPR構築像やMRCPでは膵頭部主膵管に狭窄と思われる不明瞭な所見を認めた．EUS，IDUSでは比較的高エコーパターンを呈した腫瘍と，腫瘍の一部が主膵管内へ突出，進展している所見が認められた．主膵管進展を呈した膵腫瘍の診断にて，幽門輪温存膵頭十二指腸切除術が施行された．病理組織学的には腫瘍は増生した繊維性間質を伴った微小な嚢胞で構成され，漿液性嚢胞腺腫と診断された．腫瘍は主膵管を圧排し，管腔内への突出，進展も認められた．過去に主膵管内進展を呈した膵漿液性嚢胞腺腫の報告例はなく，非常に興味深い症例と思われた．