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The synthesis, structure and properties of new yttrium dichloro, dialkyl and bis(triethylborohydride) complexes coordinated by N,N'-diisopropyl-N'-bis(trimethylsilyl)guanidinate ligand are described. This ligand has allowed the synthesis and isolation of new monomeric salt-free yttrium complexes.

We have observed a dramatic dependence of the extreme ultraviolet (EUV) reflectivity of Mo/Y multilayers on the oxygen content of yttrium. This is explained as being due to a change in the microstructure and an increase in roughness of the yttrium layers and not just to an increase in absorption owing to the amount of oxygen within the yttrium layers. We found that the best reflectivity of 38.4% was achieved with an oxygen content of 25%, which was reduced to 32.6% and 29.6% for multilayers manufactured from oxygen-free yttrium and 39%-oxygen yttrium, respectively. These results highlight the importance of including experimentally determined optical constants as well as interface roughness in multilayer calculations. In addition, the lifetime stability of Mo/Y multilayers with different capping layers was monitored for 1 year. The molybdenum- and palladium-capped samples exhibited low surface roughness and ~4% relative reflectivity loss in 1 year. The relative reflectivity loss of the yttrium-capped sample (yttrium with 39% oxygen) was ~8%. However, the reflectivity loss in all three capping layers occurred within the first 100 days after the deposition, and the reflectivity remained stable afterward. OCIS codes: 230.0230, 230.4170, 310.0310, 310.6860.

This article investigated the structural, transport, and magnetic properties of a series of samples in which the La(sub 0.67)Sr(sub 0.33)MnO3 (LSMO) layer thickness is fixed at eight unit cells and that of YBa2Cu3O7(YCBO) varied from one to six cells. Magnetic moment measurements present a qualitative agreement with the model.

A study was conducted to investigate the reactivity of yttrium atom towards ammonia at room temperature in a fast-flow reactor. The molecular orbital analysis indicated that ammonia molecules were ligated to the positive end of the large dipole of YNH through dipole-dipole interactions and dative bond formations.

A study is conducted to examine the growth and stability of an iron oxide overlayer on yttria-stabilized zirconia with the help of stomic layer deposition (ALD) in combination with low-energy ion scattering (LEIS). These techniques form a powerful combination, where ALD is designed for controlled (sub) monolayer deposition, while LEIS probes the altered outermost atomic layer.

Research on nanocrystalline cubic yttria is examined in detail. The luminescence is calculated, and explanations are provided, with a discussion of results.

Research into the structure of Pd capped Y films for use as a switchable mirror is presented. It was established that the strong binding of oxygen and yttrium produces an oxygen induced surface segregation supplying a surface with reduced hydrogen adsorption.

Brillouin spectroscopy was used to measure single-crystal elastic moduli of yttria.

Research has been conducted on the terphenyl derivatives of trivalent ytterbium, thulium and yttrium. The molecular structures of these derivatives have been investigated and the results are reported.

Ce-substituted yttrium iron garnet thin films were grown onto single crystal Gd3Ga5O12 (111) substrates, and crystalline, magnetic and magneto-optic properties were studied.

Yttria Stabilized Zirconia layers were deposited on metal tape using modified magnetron sputtering.

A modified Czochralski technique was used to grow Nd-doped yttrium orthovanadate crystals.

A new form of mesoporous yttria-zirconia materials suitable as electrode materials in solid oxide fuel cells, have been synthesized.

The compounds Y[N(QPPh2)(sub 2)](sub 3) (Q = S, Se) are synthesized in good yield from the protonolysis reactions between Y[N(SiMe3)(sub 2)](sub 3) and HN(QPPh2)(sub 2) in methylene chloride (CH2Cl2). The conformations are shown to exist in solution through (super 89)Y, (super 77)Se, and (super 31)P NMR spectroscopies and in the solid state through X-ray crystallography.

Extended X-ray absorption fine structure and X-ray absorption near edge structure spectroscopies have been used to analyze the solvation structure of the yttrium(III) cation in aqueous dilute and concentrate solutions.

A new study investigates the local order and magnetic behavior of thin epitaxial films of gallium or scandium-doped and undoped yttrium iron garnet produced by swift heavy ion irradiations.

Nonuniform bias magnetic field was used to study the nonlinear properties of magnetostatic forward volume wave-based guided-wave magnetooptic Bragg cell modulators in bismuth-substituted yttrium iron garnet-gadolinium gallium garnet waveguides.

Issues concerning the hydration of the yttrium(III) ion in aqueous solution are presented. The ion is found to be hydrated by eight water molecules in aqueous solution.

Thin films of gamma-phase yttrium trihydride YHx transmission spectra was measured at room temperature.

A new study investigates the effect of Yb3+ doping on upconversion emission intensity in Er3+/Yb3+-codoped fluorzirconate glasses.

The alkoxide method was used to prepare nanoscale amorphous yttrium-iron-garnet particles.

Research was conducted to examine the temperature dependence of the properties of heteroepitaxial Y2O3 films grown on Si by ion assisted evaporation. Reflection of high energy electron diffraction, X-ray scattering, Rutherford backscattering spectroscopy channeling, atomic force microscopy and transmission electron microscopy were used to investigate the film properties such as crystallinity, strain and morphology. Results indicate that many defects at the interface region were generated by interface interaction between the Si substrate and the yttrium metal.

Research was conducted to examine arrays with YBa2Cu3O7-Josephson junctions in ramp-edge geometry and on bicrystal substrates. Ramp-edge Josephson junctions were fabricated in arrays of three, fivve and seven junctions in series and in a mixed array with a very large number of up to two millions on one chip. Ramp-edge junction arrays were compared with bicrystal Josephson junctions by several characterization methods.

Biaxially oriented films of yttria stabilized zirconia were deposited on polycrystalline and amorphous substrates using ion-beam assisted laser deposition. X-ray texture analysis was used to examine the film texture in dependence of deposition parameters while deposited films were analyzed by transmission electron microscopy and atomic force microscopy. All films showed a columnar film growth structure. The results showed that the nucleation process was polycrystalline and independent of the ion-beam assistance.

Biaxially textured yttria-stabilized zirconia thin films served as a buffer layer for subsequent deposition of oriented YBa2Cu3Ox films. The thin films were deposited on randomly oriented Hastelloy C and stainless steel 304 at room temperature. The 0.16-1.3 microns thick YSZ films were deposited at rates of 1.2-3.2 angstroms/sec through e-beam evaporation. An Ar/O2 ion beam directed at the substrate during film growth produced biaxially textured films.

A study was conducted to analyze the pure single crystals of yttrium aluminum pervoskite and YAlO3 doped with a number of rare earth elements. The crystals were prepared using the Czochralski technique while the melts were determined based on ref 8 from high-purity oxides. Results indicated significant changes in chemical shifts and full widths at half-maximum of the signals that were caused by doping and the presence of color centers.

The influence of doping on the host crystal structure of yttrium aluminum garnet (YAG) was investigated using x-ray photoelectron spectroscopy. The consequences of doping were observed indirectly through an analysis of the peaks and variations of the chemical shifts of the main ions forming the YAG crystal. The presence of only one independent oxygen ion was proven, even though the O(1s) spectra of all YAG systems exhibit two readily discerned peaks. This dichotomy is linked to the possible polarization of the oxygen valence electron density between aluminum and yttrium.

Transmission electron microscopy in a Y-Si reaction system was used to investigate the nucleation of silicides. It was found that the amorphization due to alloying took place and the concentration gradient was formed over the alloying layer during deposition. A hexagonal YSi2 phase and a cubic Y5Si3 metastable phase were observed at the layer adjoining the Si substrate at the midmost region of the alloying layer.

X-ray diffraction, atomic force microscope and reflection high-energy electron diffraction were used to examine the initial and epitaxial growth stage of Y2O3/Si(100) grown by reactive ionized cluster beam deposition. Findings showed that crystalline growth of Y2O3 film depends on the state of the surface at the initial growth stage whether the Si surface was first exposed to oxygen or yttrium. The silicon layer which formed on the Si surface during the initial growth stage played a significant role in the epitaxial and preferred growth direction of the film.

A study was conducted to analyze the characteristics of carbon dioxide activation at metal centers in the gas phase. The reactions of Y+ and YO+ with CO2 and the reverse reactions of YO+ and YO2+ with CO2 were also examined. Ion beam mass spectrometry was utilized to carry out the analysis. Experimental results indicated that yttrium cations reacted with carbon dioxide to form two ionic products.

Research was conducted to examine the structural role of lanthanum (La) and yttrium (Y) in aluminosilicate glasses. HIgh-resolution 17O and 27 Al NMR data on a series of La and Y aluminosilicates demonstrate the significant increase in concentrations of AlO5 and AlO6 groups resulting from the smaller radii and higher field strengths of the modifier cation. Results suggest major effects on network speciation that vary considerably from Y to La and that place new constraints on the type and extent of compositional clustering.

The homogeneous precipitation method was used in the synthesis of the layered and hexagonal yttrium-based surfactant mesophases templated by anionic surfactant (C(sub n)H(sub 2n + +)OSO(sub 3)(super -)) and C(sub n)H(sub 2n + 1)SO(sub 3)(super -) assemblies. Experimental results showed that the specific surface area of the mesostructured solid increases for both the layered and hexagonal forms. In addition, the anion-exchange of the hexagonal mesophase with acetate species leads to a mesoporous material with a specific surface area of as large as 545 m(super 2) g(super -).

A photoelectron spectroscopic (PES) study was performed on scandium (Sc) and yttrium (Y) oxide species, ScO(sub n)(super -) (n=1-4) and YO(sub n)(super -) (n=1-5), respectively, to further understand the electronic structure and chemical bonding between Sc, Y and oxygen. The PES technique determined the size-selected electronic structure and spectra of gas-phase oxides. It was revealed that ScO and YO had the same electron affinities with similar excitation energies for their excited forms.

Research was conducted to examine the synthesis and structure of a new type of sandwich-like yttrium complex derived from tetraphenylethylene: (Na(THF)6)(Y(Ph2CCPh2)2). Complexes of the general formula (M(THF)x)(Y(Ph2-CCPh2)2) undergoes cation exchange with NaBPh4 in THF to form crystals of (Na(THF)6)(Y(Ph2CCPh2)2)(THF)2. The anionic unit (Y(Ph2CCPh2)2)- possesses a sandwich-like structure in which each (PhCCPh2)2- dianion has six carbon atoms oriented toward the metal center with Y-C distances that range from 2.518(6) to 2.689(7) angstrom.

Research was conducted to determine the viability of using organoyttrium complex Cp*2YCH3.THF to catalyze the sequential cyclization/silylation of suitable dienynes. The catalyst is equipped with the ability to react selectively with the substrates with the reactions proceeding at reasonable rates under the mildest conditions. This method can be used to extend other catalyzed cyclization reactions of enynes and polyenes and does so in a way that is atom economical.

A study relating to thermodynamic research on gaseous transition-metal carbides was conducted to determine the equilibrium molecular structures of dimetal carbide Y2Cn (N = 2-8) from which the partition functions and thermodynamic properties are computed. Among other results, it was found that the ground-state isomers of diyttrium carbides exhibit cyclic structures in contrast to pure carbon clusters which are linear for n less than 10.

Experiments were performed to investigate the synthesis and structural characteristics of the Aveiro microporous solid no. 1 (AV-1). AV-1 is the first artificial microporous yttrium silicate. In addition, the chemical structure of montregianite, of the rare mineral rhodesite and alkali calcium silicate hydrate AV-2 were examined. Scanning electron microscopy, magic-angle spinning nuclear magnetic spectroscopy and other analytic techniques were employed. The AV-1 and AV-2 exhibited similar double silicate layers.

The reactions of yttrium and lanthanum atoms with nitrogen were studied. The results showed that laser-ablated Y ad L atoms react with nitrogen to form metal nitrides and dinitrogen complexes. On the other hand, thermally evaporated Y and L atoms have produced dinitrogen complexes. It is shown that the two Y or two LA atoms can reduce molecular nitrogen to the open rhombic dimetal nitride, which is a nitrogen-fixation reaction.

The deposition temperature and the amount of oxygen (O2) gas used during the deposition process have a strong influence on the microstructures of yttrium oxide, Y2O3, films prepared by pulsed laser deposition in the presence of O2 gas. Atomic force microscopy has been used to observe very smooth surface morphologies with average surface roughness of 0.4 nm to 19 nm for films deposited on either fused silica or silicon substrate between 150 degrees C and 650 degrees C. These films also show a good waveguiding property.

The possible use of arylamide ligands is examined in yttrium and lanthanide complexes and in the preparation of mixed-metal organometallic complexes using aluminum. Arylamido groups as ligands for yttrium and lanthanide metals afford products of different structural forms. Moreover, the products are soluble and stable enough to be analyzed in crystal form. The syntheses can also be extended to the preparation of metals of large and small radii.

The formation and structural characteristics of hetero(poly)metallic complexes ClM(OAr)3Na (M = Lu, Y) and ClY(OAr')3Y(OAr')3Na with the bis (OAr = OC6H2 CH2NMe2 2-2,6-Me-4) and mono (OAr'= OC6H4 CH2NMe2 -2) o-amino substituted phenolate ligands were studied with the use of nuclear magnetic resonance spectroscopy and X-ray structure analyses. The structure formations of the complexes were described to be the outcome of the cooperative anion-cation bonding. This observation was used in the proposal for the synthesis of new organometallic polymers.

A comparative study shows that yttrium (Y) and rare-earth elements (REE) are closely related in fluorite-precipitating solutions. Non-chondritic Y/Ho ratio is varying, up to 200, for hydrothermal vein fluorites, which is in contrast to igneous and clastic rocks. In fluorine-rich medium-temperature aqueous fluids , Y and Ho may be fractionated. The details of the comparative study, its results and discussion are given.

The growth rate and mechanism of growth of ion-stimulated yttrium silicide layers are measured using inert ions. The growth rates are determined with respect to fluence and nuclear energy deposition at the Y Si interface. The yttrium silicide layers are formed after ion-induced phase transformation in amorphous-Si Y bilayers.

Analysis of the structures of La3In5 and Y3In5 by X-ray diffraction experiments reveals that both compounds have distinct square-pyramidal In5 units. In-In separations are longer in the lanthanum compounds compared to those in yttrium compounds. Presence of In(sub 5)(super 9-) cluster in La3In5 and small valence electron delocalization make La3In5 to be considered as a metallic zintl phase. At low temperatures clusters in Y3In5 phase form a three-dimensional structure.

X-ray crystallographic studies enable the determination of the crystal structure of Y(OSitBuAr2)(N(SiMe3)2)2 (Ar = o-C6H4(CH2NMe2)), formed by a reaction of Y(N(SiMe3)2)3 with a new arylsiloxide OSitBuAr2. Addition of 2, 6-di-tert-phenoxide to the yttrium complex leads to replacement of silylamides, producing a phenoxide complex. A metathesis reaction between LiR and the phenoxide complex eliminates LiOC6H3tBu2-2,6 without ligand distribution forming an anionic dialkyl complex.

Recrystallization of YCl3(3.5)THF from tetrahydrofuran and from dichloromethane yields the (trans-YCl2(THF)5)(trans-YCl4(THF)2) salt and the (YCl3(2)THF)(infinite) polymer, respectively. X-ray diffraction studies show that the cation of the salt has an yttrium atom that is seven-coordinated, with five pentagonal oxygen atoms of the THF molecules and two trans-coordinated chlorine atoms. Double chlorine bridges link the seven-coordinated yttrium atoms in the polymer.

Potentiometric and spectrophotometric methods help calculate ligand protonation constants of three macrocyclic poly(amino carboxylates) and stability constants of their Gd(III) and Y(III) complexes at 25 degrees Celsius and constant ionic strength. Na+ ions decrease the protonation constants, revealing the coordination of ligands with Na+. X-ray analysis helps the structural characterization of isostructural Gd(III) and Y(III) complexes of HP-DO3A, H2SO4 salt of DO3A and the (Na(tBu-DOTA))Br complex.

An analysis of the electric properties of tantalum oxide (Ta2O5) based composite films reveals that the addition of Y2O3 or WO3 improves the films' insulating properties. Oxide-added Ta2O5 films have double the storage charge capacity of Ta2O5 films. The additive oxides compensate for excess-oxygen induced charge, resulting in improved properties.