Single crystals of Y4PtGa12 have been synthesized and characterized by X-ray diffraction. The compound crystallizes in the cubic Im3m space group with lattice parameters a = 8.530(5) Å. Magnetic property measurements show that Y4PtGa12 does not order magnetically. Structure-property relationships with the isostructural antiferromagnet Tb4PtGa12 are discussed.

β-FeSi2 was successfully fabricated at room temperature via the deposition of molten micro-droplets generated by the KrF excimer laser ablation. Only the molten droplets precipitated as the β-FeSi2 crystalline phase on a silicon substrate kept even at room temperature, whereas the rest of film was amorphous. The crystallization behavior of micro-droplets has been discussed in the light of non-equilibrium process due to rapid cooling on the substrate. After the deposition, pulsed laser annealing was also performed in order to improve the crystallinity of the β-FeSi2 microprecipitates-containing film.

Preparation of NiNb2O6 columbite ceramics by a reaction-sintering process has been investigated. The mixture of raw materials was pressed and sintered into ceramics without any calcination stage involved. Columbite NiNb2O6 ceramics were obtained after being sintered at 1250–1450°C for 2 h and 4 h from mixture of Nb2O5 and 50%Ni(NO3)2-50%NiO (NN1). In pellets from mixture of Nb2O5 and NiO (NN2), columbite NiNb2O6 ceramics were obtained after being sintered at 1150–1350°C for 2 h and 4 h. A density of 4.47 g/cm3 was obtained in NN1 for 2 h sintering at 1400°C. For NN2, a higher density 5.62 g/cm3 (99.8% of the theoretical value) was obtained for 2 h sintering at 1300°C. The reaction-sintering process has proven to be a simple and effective method in preparing columbite NiNb2O6 ceramics. A higher density could be obtained at lower sintering temperature by using NiO instead of 50%Ni(NO3)2-50%NiO in the reaction with Nb2O5.

Amorphous silica films deposited by Combustion Chemical Vapor Deposition (CCVD) were modified by lithium addition in the precursor solution. The modified films were characterized by X-ray diffraction and scanning and transmission electron microscopy. The addition of lithium promoted the crystallization of Li2O-SiO2 compounds, mainly crystalline phases like Li2SiO3, Li2Si2O5, quartz and cristobalite. Besides that, the morphology of the film was modified, leading to the formation of acicular structures and nanowires. The acicular structures were identified through TEM associated with SAED as crystalline phases, mainly constituted by Li2SiO3 and Li2SiO5. TEM and SEM analysis indicated that the nanowire diameter is between 20 and 80nm. In addition to this, SAED and microprobe EDS analysis indicated that these nanowires are constituted by amorphous silica. The probable growth mechanism of these nanowires is the vapor-liquid-solid (VLS) catalyzed by a liquid particulate composed by Li2O-SiO2.

We contrast the interaction of mercury with adsorbed orthocarborane films and semiconducting (dehydrogenated) boron carbide. Photoemission spectra reveal small shifts in orthocarborane (C2B10H12) molecular orbital binding energies as well as the shift in mercury 5d5/2 shallow core level binding energies, suggesting only small interaction between mercury and the molecular film. Mercury does, however, interact with decomposed orthocarboranes i.e. semiconducting boron carbide.

The concept of chemical hardness was originally developed as a measure of the stability of molecules. Its relationship to physical hardness and to solids is demonstrated here. Also, it is shown that shear moduli, and polarizabilitites, as well as band gaps are related to chemical hardness. Finally, evidence is presented that indentation hardness numbers are better measures of critical phase transition compressions than “pressure-cell” data.

Poly(norbornenyldecaborane) (PND) was synthesized via ruthenium catalyzed ring opening metathesis polymerization and was found to be a good single-source polymeric boron carbide precursor. Polymer blends of PND and allylhydridopolycarbosilane (AHPCS) were also found to be excellent precursors to boron-carbide/silicon-carbide composite materials.

We report synthesis and properties of layered compounds with 2D boron-and-carbon-mixed-atomic-layers which are related to topics of recent high interest. The previous discovery of the first [B/C] graphite intercalation-like compound Sc2B1.1C3.2 and evaluation of reported high temperature ferromagnetism in CaB2C2 are reviewed. MgB2 related [B/C] compounds MgB2C2 and LiBC were synthesized and hole doping carried out in search for superconducting materials with high TC. Superconductivity was not observed for any of the compounds above 1.8 K, but (Mg, Li)B2C2 is demonstrated to be the most promising system, with an insulator to metal transition indicated to be induced.

A systematic hierarchical evolution of nanowires, nanorods, and nanosheets in ZnO, based on a oxygen-assisted carbothermal reduction process, was presented. Nanowires, nanorods, and nanosheets were synthesized in series with controlling oxygen partial pressure from 10-6 to 10-1. It was impossible to get ZnO nanowires with using Ar gas only and more than 1ppm of oxygen could successfully introduce the ZnO nanowires on the Si substrates at the downstream of the tube. The additional oxygen gas with Ar carrier gas could introduce not only the nanowires but also the combs and sheets. The details of nanocombs and nanosheets also were presented.

ZnO nanorods were synthesized by a hot-wall type pulsed laser ablation process. At temperatures 500∼800°C, ZnO thin films and wrinkles were synthesized. Above 800°C, vertically aligned ZnO nanorods were grown on the Si and sapphire substrate without any catalysts. The range of diameter was 100∼300nm. When Au catalyst were deposited on the substrate prior to the deposition, the process range of ZnO nanorod become wider and the diameter of ZnO narrower. Especially, ZnO could be grown selectively along the pattern of Au catalyst with the aid of Au-Zn alloy.

Combinatorial and high throughput methods have been utilised in the pharmaceutical industry for many years. The process involves the simultaneous synthesis of libraries containing thousands of compounds, which can then be screened for desirable properties. More recently the concepts of parallel synthesis and high-throughput screening have emerged as effective strategies in the search for novel inorganic materials. We report the development of high throughput methods, which have been used for the synthesis and preliminary characterisation of ceramic oxide pigments on an alumina substrate. This methodology has been utilised to prepare compounds with the spinel structure in the series Cu1-xZnxAl2-yCryO4 (0≤x≤1, 0≤y≤2) at a range of temperatures. The materials are analysed by rapid sequential X-ray diffraction and a simple colour measurement technique. The optical properties across the quaternary landscape can therefore be mapped as a function of composition, structure and annealing temperature.

The magnetic properties of the first hollandite-type vanadium oxide containing anions in the 2×2 channels, V7.22O8(OH)8(Cl)0.77(H3O)2.34, are studied using static (DC) and dynamic (AC) magnetic susceptibilities. From the high-temperature Curie-Weiss behavior the effective magnetic moment is found consistent with the 3+ vanadium oxidation state; the negative Curie-Weiss temperature Θ ≈ -500 K indicates strong antiferromagnetic exchange. The DC magnetic susceptibility shows a rapid increase and the AC susceptibility shows a maximum at about 20 K, indicating magnetic phase transition. The field-cooled and zero-field-cooled susceptibilities diverge below the transition temperature. The real and imaginary components of the AC susceptibility show frequency dependence and shift of maximum toward lower temperatures with decreasing frequency. Analysis of the frequency dependences reveals at least three different relaxation processes existing around and below the transition temperature. The temperature dependences of their relaxation times were obtained using Cole-Cole analysis. We show that the magnetic behavior observed is well explained by the random-field Ising model, with randomness brought on by vacancies in vanadium sites.

Four open-framework copper titanosilicates have been synthesized by hydrothermal techniques. The crystal structure of Phase 1 determined from single crystal X-ray data is closely similar to that reported for the titanosilicate ETS-4 with ca. one third TiO5 pyramids randomly replaced by CuO4 squares. Phase 2 also has the ETS-4 structure but all the TiO5 pyramids are replaced by CuO4 squares which are not randomly disordered. Phase 3 with the composition Na8CuTi3Si16O43 has the same structure as the mineral narsarsukite, a titanosilicate closely related to the microporous titanosilicate ETS-10. Narsarsukite and ETS-10 have the same straight single chains of TiO6 octahedra which are partially substituted by CuO4 squares in 3. Phase 4 with the composition K4CuTiSi8O21 contains CuO4 squares and TiO5 tetragonal pyramids that crosslink a new type of silicate double layer to form an open framework.

We report the synthesis and thermoelectric properties of [(Ca1-xREx)2CoO3-δ]0.62CoO2 compounds (RE: rare earth element, RE = Y, Sm, Eu, Tb, Dy, Ho and Lu). From optimization of synthesis conditions, all the chosen RE in this study were able to be substituted for the Ca sites in the block layers up to x = 0.25. In the case of RE = Tb, at 1150 K, only κ was systematically decreased with x, while both Seebeck coefficient (S) and resistivity (ρ) were almost constant for the charge of x. Consequently, the dimensionless figure of merit (ZT) was increased with x and reached 0.2 at 1150 K for x = 0.25. Moreover, interestingly, it was found that S and ρ at 300 K were enhanced with ionic radius of the doped trivalent RE ions in spite of the doping of equivalent RE ions. This is probably because local structures of oxygen sites around Co ion in the CoO2 layers largely depend on kinds of the doped RE.

Bond valence sums (BVS) calculated for lone-pair cations are found increasingly higher than their formal valences as the retraction of the lone electron pair (LEP) from the nucleus is more pronounced. The increase in BVS is interpreted as a continuous increase of an effective valence of an atom that is a measure of its actual ability to bind other atoms without changing its formal valence. How the LEP of a lone-pair cation affects the effective valence of other atoms in a structure is studied by bond valence calculations for specific structures. For structures rich in alkali cations, it is found that the high effective valence of the lone-pair cations tends to be balanced by low effective valence of alkali cations. The LEP transfers bonding power or effective valence from the alkali cations to the lone-pair cations by joining the coordination sphere of the alkali cations.

This paper reports our findings for the effect of the glass composition on the local environment of the thulium ions in the glass structure and its spontaneous and stimulated emission probabilities in the infrared region at room temperature. Absorption measurements in the UV/VIS/NIR region were used to determine spontaneous emission probabilities for the 4f-4f transitions of the thulium ion. Six bands corresponding to the absorptions of the 1G2, 3F2, 3F3, 3F4, 3H5, 3H4 from the ground level were observed. Integrated absorption cross-section of each band except that of 3H5 level was found to vary with the glass composition. Luminescence spectra of the samples were measured upon 785nm using a diode laser. Two emission bands centered about 1500nm and 1800nm were observed.

The effect of the glass composition on the Judd-Ofelt Parameters and therefore on the spontaneous emission probabilities for the metastable levels of thulium ions will be discussed in detail.

In this MRS Proceedings paper, we present a review of the floating zone growth process, and describe growth techniques as relevant to four selected families of current or continued interest in the area of condensed matter physics of highly correlated electron systems: Cuprate oxides (Bi2Sr2CaCu2Oy), Ruthenate oxides (Sr2RuO4), Manganite oxides (La1-xSrxMnO3, La2–2xSr1+2xMn2O7, (RE) MnO3 (RE=Rare Earth)) and Ferrite oxides (BiFeO3). We also discuss our experiences with factors that tend to contribute to poor crystal growth, as relevant to experiments to probe correlated-electron physics in such crystals.

We have used precursor routes to prepare magnetic transition metal ion (tM) substituted wurtzite ZnO powders with up to 15% tM substitution (tM = Co and Mn) on the cation site. Careful magnetic studies reveal these samples show no cooperative magnetic ordering, and certainly no ferromagnetism. Instead, the nearest-neighbor coupling is actually antiferromagnetic. Modeling of the temperature dependence of the magnetic susceptibility indicates the difficulty in inducing ferromagnetism, in keeping with the results of density functional calculations. The alternate strategy of inducing dilute ferri magnetism in wide band gap spinel hosts with two cation sites has been more successful; dilute magnets based on tM substitution in spinel ZnGa2O4 seem promising, displaying magnetic hysteresis in nearly transparent samples.

We present a study of CdSe nanocrystals synthesized in MgO by precipitation of Cd and Se supersaturated solid solutions, created in MgO single crystals by ion implantation, in the temperature range between 300 °C and 1100 °C. For high-dose ion implantation, optical absorption spectroscopy revealed the presence of the ∼1.8 eV CdSe semiconductor band-edge. Small sized nanocrystals adopt the rocksalt instead of the wurtzite structure because the former fits better in the MgO matrix and results in lower interface energies. A better understanding of these structural changes and optical properties is obtained from ab-initio total energy calculations on wurtzite, zincblende and rocksalt CdSe using the VASP pseudopotential code. The calculated electronic band structures are compared of zincblende CdSe, a direct band-gap semiconductor, and rocksalt CdSe, which has an indirect optical band-gap.

A study on the comparison of porous TiO2-SiO2 mixed oxides synthesized variously via the “amine directed” method is reported. The amine capping groups were octylamine, dodecylamine, octyldecylamine, aniline, and isobutylamine. The mixed oxide is characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), infrared spectroscopy (IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Brunauer-Emmett-Teller analysis (BET). While XRD, SEM and TEM provide mainly (bulk) structural information on the mixed oxide preparations, BET (N2 physisorption) probes into their surface area and texture. IR evidence suggests that intimate chemical mixing of both oxides has occurred, while BET measurements show that high surface areas are attainable and that the mixed oxide is more thermally stable than pure (control) samples of TiO2.