Search

The ceramic liquid droplet of Cu[O.sub.x]-added Bi[O.sub.x] at high temperature in vacuum is studied. The Cu[O.sub.x]-added Bi[O.sub.x] is found to be stable in the liquid phase at high temperature in vacuum, making it useful for cleaning the CaO impurities on MgO single crystal surface, resulting in the preparation of the atomically flat MgO(001) surface.

Two new phosphates, [Bi.sub.4.25][(PO4)2[O.sub.3.375] and [Bi.sub.5][(PO4)2[O.sub.4.25], are synthesized and analyzed by single-crystal X-ray diffraction in the series of [Bi.sub.4+x][(PO4)2[O.sub.3+3x/2] (0.175

The synthesis, structures and reactions of R2Bi-BiR2 [1, R = 2,6-(Me2NCH2)C6H3], a tetraaryldibismuthane with protection by eight pendent amino groups, are presented. The compound 1 reacts with air to form the peroxide [R2Bi](sub 2-)(O2) (2) and R'R''Bi [3, R' = 2-(Me2NCH2)-6-{Me2N(O)CH2}C6H4, R'' = 2-{Me2NCH2)-6-{O(O)C}C6H3], and a mononuclear bismuth complex where the pendant Me2NCH2, a mononuceleaser bismuth complex where the pendent Me2NCH2 groups are partially oxidized.

Bismuth vanadate (BiVO(sub 4)) nanosheets were synthesized hydrothermally in the presence of a morphology directing agent sodium dodecyl benzene sulfonate (SDBS) and were studied with the help of modern techniques of spectroscopy and electron microscopy. The BiVO(sub 4) nanosheets showed a monoclinic structure with a preferred surface orientation, outstanding spectral selectivity, improved color properties and higher photcatalytic activities.

The microstructure and magnetotransport properties of sputtered Bi upon annealing are investigated. The magnetoresistance (MR) of Bi films is strongly dependent on the microstructure and thickness of the films and on the measured temperature, and hence the measured temperature and film thickness on which the phonon scattering relies are very important factors in determining the MR of sputtered Bi films.

The thermoelectric properties of bulk as well as thin films of Bi93Sb7, grown by vacuum flash evaporation technique, are analyzed. The scattering index parameter is calculated in both as-grown and annealed films and it is observed that both the electrical conductivity and thermoelectric power of annealed films are larger than those of as-grown films.

The electronic structure of strontium bismuth tantales (SBT) thin films has been discussed by x-ray photoelectron spectroscopy and ultraviolet-ray photoyield spectroscopy (UV-PYS). The high-pressure-O2 annealing tends to suppress current through the pyrochlore-dominant MOD-SBT thin films, which is considered to be partly because bismuth oxides other than (Bi2O2)(super 2+) layers have been produced at the surface by high-pressure-O2 annealing.

A new quasi-one-dimensional compound Ni8Bi8SI is synthesized and its crystal structure determined from single-crystal x-ray diffraction data. Analysis of chemical bonding reveals strong multicenter Ni-Bi bonds and pair Ni-S interactions within the compound.

X-ray diffraction, vibrating sample magnetometer and Mossbauer spectroscopy are used for studying the crystallographic and magnetic properties of [Tb.sub.3-x][Bi.sub.x][Fe.sub.5][O.sub.12] (x = 0.5, 0.75, 1.0 and 1.25). The saturation magnetization at room temperature has increased linearly with increase of bismuth concentration, which is due to the strong exchange interaction between a and d sublattices with increase of bismuth concentration.

The electronic structure of K3Bi2 is discussed on the basis of first-principles density functional theory (DFT) calculations. Only the valence electrons are considered in the calculation, with the core being replaced by norm-conserving scalar relativistic pseudopotentials factorized in the Kleinman-Bylander form.

Magnetic measurements and neutron diffraction techniques were used for examining the magnetic structure of high purity MnBi low temperature phase. A coercivity of 2.0 T at 400 K and a positive temperature coefficient from 0 to at least 400 K is observed in the low temperature phase of the MnBi alloy.

A one-pot solution process is devised for preparing colloidal [Bi.sub.2][Te.sub.3]-Te heterogeneous nanostructures (HNs) that comprise [Bi.sub.2][Te.sub.3] nanoplates and Te nanorods. The synthesis of [Bi.sub.2][Te.sub.3]-Te HNs has provided opportunities for producing thermoelectric materials with enhanced performance.

The transmission electron microscopy technique is employed to explain the domain morphology and crystal structure exhibited by the lead-free (1-x)([Bi.sub.1/2][Na.sub.1/2])Ti[O.sub.3]-xBaTi[O.sub.3] ceramics. The correlation existing between the domain structure and frequency dispersion of dielectric constant is also analyzed.

The x-ray and neutron powder diffractions techniques are employed to explain the structural, as well as the piezoelectric properties exhibited by the high-density ([Bi.sub.0.5][K.sub.0.5])Ti[O.sub.3]-BiFe[O.sub.3]ceramics. The results demonstrate the presence of a morphotropic phase boundary between the different phases of the ceramics.

Several studies are conducted to explain the structural, magnetic, as well as the transport properties exhibited by the [Bi.sub.0.6][Ca.sub.0.4]Mn[O.sub.3] compounds. The various impacts caused by the progressive substitution of the Bi ion by the La ion on these properties are also analyzed.

The article presents a new approach, where in Te nanowires made via the solvothermal method are used for the synthesis of [Bi.sub.2][Te.sub.3] nanotubes. The microstructure of the Te nanowires is shown to exhibit a significant impact on the alloying taking place between Bi and Te in the nanotubes.

Several studies are conducted to explain the different magnetic properties of the La doped [Bi.sub.2]FeMn[O.sub.6] ceramic and film deposited by the pulsed laser deposition method. The film is shown to exhibit an antiferromagnetic or a weak ferrimagnetic behavior at the room temperature.

The lattice evolution of BiFe[O.sub.3] is described as function of temperature by using far infrared emissivity, reflectivity and x-ray absorption local structure. The local structural measurements have shown high temperature defect-induced irreversible lattice changes, below and above the ferroelectric transition, in an environment of lacking of long-range coherence.

Electrical spin injection and detection are examined at cryogenic temperatures by using a lateral spin-valve structure, where Bi or BiPb is used as a nonmagnetic spin medium, while CoFe and NiFe are used as the spin injector and spin detector. The studies have shown that the interfacial spin polarization and the associated spin accumulation are correlated very strongly with the interfacial resistance.

Ab initio calculations based on density functional theory are used for studying energetic, structural, electronic and optical properties of Cr doped [Bi.sub.4][Ge.sub.3][O.sub.12] (BGO). The comparison with the experimental BGO:Cr absorption spectrum has shown that it has both [Cr.sup.3+] and [Cr.sup.4+] contributions, displaying the Cr simultaneous presencef at both substitution sites.

The article explains the synthesis and the structural, dielectric and magnetic properties of the multiferroic [Ba.sub.4][Bi.sub.2][Fe.sub.2][Nb.sub.8][O.sub.30] compounds. The coupling behaviour exhibited by the compounds is also analyzed.

Several x-ray diffraction analyses are conducted to explain the microstructure, as well as the electrical properties of the Aurivillius phase ferroelectric solid solutions of [(Ca[Bi.sub.2][Nb.sub.2][O.sub,9]).sub.1-x][(Ba[Bi.sub.2][Nb.sub.2][O.sub.9]).sub.x] compounds. The relaxation behaviour exhibited by the compounds at high concentrations is also analyzed.

Several studies are conducted to explain the properties and the impact of substrate orientation on the lattice relaxation of the epitaxil BiFe[O.sub.3] thin films. The structural properties of the films are shown to be highly dependent on the substrate orientation.

Several studies are conducted to explain the structural, magnetic, as well as the magneto-transport properties of the various different Pt-alloyed MnBi thin films. An increase in the concentration of Pt in the films is shown to lead to a decrease in their saturation magnetization.

A combination of the X-ray diffraction and scanning electron microscopy technique is employed to explain the low temperature synthesis and the magnetic and structural characterization of the manganese sillenite [Bi.sub.12]Mn[O.sub.20] compounds. The relaxation time of the compounds is shown to be completely field dependent.

Electrically stressed Bi-Sb-Te thin films have shown enhanced Hall mobility and moderately reduced carrier concentration and to reduce electrical resistivity, a Sb-inserted Bi-Sb-Te multilayer structure is prepared by consecutively sputtering Bi-Sb-Te and Sb layers followed by electric current stressing. The method has provided a way to optimize thermoelectric properties of Bi-Sb-Te films.

The article discusses a new methodology, where in an ultrafast optical Kerr gate of the bismuth glass can be used for the measurement of shapes of the objects in an ultrafast time-resolved imaging system. The technique is shown to be much more beneficial and advantageous, as compared to the other conventional methods.

The utility of bismuth(III) triflate as catalyst for the direct conversion of corticosteroids into highly functionalized 17-ketosteroids by cleavage of the C17-dihydroxyacetone side chain is described. The catalytic process is very chemoselective, since functionalities of the starting corticosteroids have remained intact.

BiFe[O.sub.3] films with different thicknesses and crystallographic orientations are grown on LaNi[O.sub.3]-buffered Si substrates by a modified chemical route. The studies have shown a competition between ferroelectric and magnetic behaviors as the film thickness has changed and magnetoelectric coupling is observed in the BiFe[O.sub.3] films with a magnetic-field-induced electrical voltage.

X-ray crystallography at 2.10 [Angstrom] (Rfree = 0.257), 1.98 [Angstrom] (Rfree = 0.281), and 1.90 [Angstrom] (Rfree = 0.228) resolution was utilized to determine the structures of three compounds (SBi132, SBi1279, and SBi523) bound to [Ca.sup.2+]-S100B. The findings for SBi132, SBi279, and SBi523 bound to proximal sites on [Ca.sup.2+]-S100B could be applied to design a new class of molecule(s) that interacts with one or more of these binding sites simultaneously, and obtain novel tight binding inhibitors specific for blocking protein-protein interactions involving S100B.

Microwire sample arrays with diameters from 2 to 25 [mu]m and polycrystalline bulk bismuth are used to examine their wire-diameter dependencies and seebeck coefficient and resistivity. The temperature dependence of the seebeck coefficients of all samples are similar to that of the bulk and the resistivity dependence of the 2-[mu]m-diameter microwave array sample have a small positive temperature coefficient which is quite different from the other samples.

X-ray diffraction and Raman spectra studies are performed for BiFe[O.sub.3] films with different thickness grown on the LaNi[O.sub.3]-buffered Si (100) substrates via a sol-gel spin-coating processing. The results revealed that the magnetic moment of BiFe[O.sub.3] films decreased back to the ordinary canted antiferromagnetic state with the increase in the film thickness.

The structural and resistive anisotropy is analyzed for the [Bi.sub.0.4][Ca.sub.0.6]Mn[O.sub.3] films grown on (011)-oriented SrTi[O.sub.3] substrates. The features of the lattice effects are useful for designing the artificial materials and devices.

The solid state reaction method is used for fabricating crystalline solutions of 0.57([Bi.sub.1-x][La.sub.x])Fe[O.sub.3]-0.43PbTi[O.sub.3] (BLF-PT) for x = 0, 0.1, 0.2 and 0.3. BLF-PT of x=0.2 has displayed multiferroic characteristics with the simultaneously enhanced remnant magnetization and polarization.

The interfacial and frequency dependent electrical properties of metal-ferroelectric-insulator-semiconductor capacitors with Sr[Bi.sub.2][Ta.sub.2][O.sub.9] (SBT) ferroelectric films grown on Zr[O.sub.2] buffer layer coated Si are examined. The charge retention time of the ferroelectric capacitor is analyzed as a function of buffer layer thickness.

A detailed study was conducted to explore the crystal structure and properties of epitaxial thin films of BiSc[O.sub.3]. The results suggested that the epitaxial thin films of BiSc[O.sub.3] on SrTi[O.sub.3] retain the principal structural features of the bulk ceramics synthesized at high pressures that give rise to a pseudo-orthorhombic unit cell.

The oxidation of americium to the pentavalent and hexavalent states using sodium bismuthate in strongly acidic solution is described. The oxidized americium was observed to be reduced by contact with the common actinide solvent extractant tributyl phosphate but by using short contact times Am[O.sub.2.sup.2+] showed behavior analogous to the lighter actinyl ions.

The x-ray diffraction method was used to examine the single crystal structure of the compound [Pb.sub.3][Bi.sub.2][S.sub.6] that undergoes a first-order phase transition at hydrostatic pressure between 3.7 and 4.9 GPa. The reversible phase transition with a preservation of the single crystal is attributed to the stereochemical influence and migration of the [S.sup.2] lone electron pairs of [Pb.sup.II] and [Bi.sup.III].

The phase structure, microstructure and dielectric and piezoelectric properties of (10x)([K.sub.0.5][Na.sub.0.5])Nb[O.sub.3]-xBiSc[O.sub.3] [(1-x)KNN-xBS] ceramics are examined. The results have provided an alternative approach for developing lead-free piezoelectric ceramics.