Second-harmonic generation of transparent glass-ceramics containing BaTiO3 crystalline phase was investigated using Maker fringe method. When 15BaO · 15TiO2 · 70TeO2 glass was heat-treated at 415 °C for 0.5–12 h, (101)- or (110)-oriented BaTiO3 crystals precipitated in the near-surface region. The resultant glass-ceramics exhibit second-harmonic generation. Variation of second-harmonic intensity with angle of incidence, i.e., the Maker fringe pattern changes drastically with an increase in heat treatment time and temperature. No second-harmonic signal was detected in glass-ceramics derived from 15SrO · 15TiO2 · 70TeO2 glass. These facts suggest that BaTiO3 crystal is responsible for the second-order nonlinear phenomenon, although its structure is closer to cubic than tetragonal according to x-ray diffraction measurements. In order to estimate second-order nonlinear optical coefficient d(2), Maker fringe patterns of the BaTiO3-containing glass-ceramics were analyzed. For the glass-ceramic after heat treatment for 0.5 h, d33 and thickness of BaTiO3-crystallized layer, L, are 3.65 pm/V and 3.43 μm, respectively. The value of second-order nonlinear optical coefficient is comparable to those of BaTiO3 films prepared via metalorganic chemical vapor deposition and pulsed-laser deposition. On the other hand, the glass-ceramic heat-treated for 12 h exhibits d15 = 0.31 pm/V and L = 300 μm. The thickness of the layer active in second-order nonlinearity evaluated from the Maker fringe pattern is coincident with the observation by scanning electron microscopy.

The formation of barium hexaferrite from stoichiometric mixtures of BaCO3 and Fe2O3 has been investigated by means of differential thermal analysis and thermogravimetry, x-ray diffraction, and transmission electron microscopy–energy dispersive spectrometry. The first step, which implies decarbonatation and monoferrite formation, includes the formation of various intermediate compounds, which are formed at contact points between BaCO3 and Fe2O3 grains, and implies diffusion of both species. In the second step, barium hexaferrite is formed at interfaces between monoferrite and iron oxide mainly by diffusion of barium through the BF6 lattice into the hematite lattice. This exothermic reaction process leads to nonagglomerated pseudohexagonal platelets with an average particle size very close to the one of the starting powder mixture (∼1 μm).

Three different kinds of morphology are found in undercooled Pd80Si20, and they dominate at different undercooling regimens ΔT, defined as ΔT = T1 – Tk, where T1 is the liquidus of Pd80Si20 and Tk is the kinetic crystallization temperature. In the small undercooling regimen, i.e., for ΔT ≤ 190 K, the microstructures are typically dendritic precipitation with a eutecticlike background. In the intermediate undercooling regimen, i.e., for 190 ≤ ΔT ≤ 220 K, spherical morphologies, which arise from nucleation and growth, are identified. In addition, Pd particles are found throughout an entire undercooled specimen. In the large undercooling regimen, i.e., for ΔT ≥ 220 K, a connected structure composed of two subnetworks is found. A sharp decrease in the dimension of the microstructures occurs from the intermediate to the large undercooling regimen. Although the crystalline phases in the intermediate and the large undercooling regimens are the same, the crystal growth rate is too slow to bring about the occurrence of grain refinement. Combining the morphologies observed in the three undercooling regimens and their crystallization behaviors, we conclude that phase separation takes place in undercooled molten Pd80Si20.

We demonstrated in “Phase separation in undercooled molten Pd80Si20: Part I” that when a molten Pd80Si20 ingot is undercooled into its undercooling regimen with ΔT ≥ 220 K (ΔT = T1 – T, where T1 is the liquidus and T is the temperature of the undercooled melt), liquid-state phase separation by spinodal decomposition occurs. On crystallization, one of the metastable liquid spinodals becomes Pd3Si, whereas the other one turns into Pd9Si2. In both cases, Pd particles precipitate out. Microstructural analysis indicates the Pd3Si subnetwork forms first. It then acts as a seed for the subsequent crystallization of the remaining undercooled melt, which finally forms the Pd9Si2 dendrites. As crystallization proceeds, latent heat and volume contraction bring about morphological changes.

The metastable liquid miscibility gap of Pd–Si is determined structurally. The glass-forming ability of Pd–Si is then discussed in the light of the metastable liquid miscibility gap. Analysis indicates that it does not favor the formation of glass.

The growth of ultrathin gold films on polyimide (PI) surfaces and the stability of the films upon thermal annealing have been studied using a combination of various techniques. With scanning electron microscopy (SEM) we observe that, at room temperature, the Au film initially grows by nucleation of compact Au islands. With increasing metal coverage, the clusters partially agglomerate to produce a wormlike structure. Finally, percolation, hole-filling, and continuous thin-film growth are observed. To evaluate the thermal stability of the Au/PI system, annealing at various temperatures was performed on films that displayed the wormlike structure. SEM results indicate strong temperature-dependent changes in film morphology. Finally, from our SEM data we determine contact angles, allowing us to estimate interfacial and adhesion energies.

The bonding structure and binding character for the initial stage of thin-film growth of Ni on a rutile (110) surface were studied using first-principles density functional theory. Our results show that, in the first monolayer, Ni atoms are preferentially adsorbed on top of bridging oxygen atoms and upon secondary surface oxygen. The bond strength between Ni adatom and substrate is much stronger than that between Ni adatoms. About 0.3 electrons are transferred from Ni atoms to substrate in low coverage; the adsorption of additional Ni atoms on neighboring sites decreases this transfer. In addition to the ionic bonding component, some covalent character is found in the Ni adatom–substrate bond.

Excimer laser pulses with wavelength of 308 nm, repetition rates of 1–10 Hz, pulse energies of 300–400 mJ, and pulse width of 20 ns are used to selectively seed palladium aggregates from a liquid-phase solution on polymer (polyimide) surfaces. The precursors used are PdCl2 in hydrochloric acid and Pd(CH3CO2)2 in acetic acid. The coverage of the polyimide with palladium aggregates is determined by the analysis of scanning electron microscopy measurements. Qualitative and quantitative analyses of seeded particles on polyimide (PI) are investigated by x-ray diffraction and transmission measurements. The amount of deposited palladium showed a quadratic dependence on the laser fluence reaching the surface. On the other hand, the coverage versus number of laser shots shows a square-root-like dependence. The palladium deposits also appear as amorphous and Pd[111] crystallites forms depending on the number of laser pulses. The roughness of a PI surface prior to seeding is modified mechanically and characterized by its fractal dimension. The fractal dimension of the samples varies between 2.3 and 2.7 for all the parameters applied, and the palladium deposition is found to be dependent on this dimension of the PI film.

We investigated various interactions between alumina and tungsten films that occur during chemical mechanical polishing (CMP). Atomic force microscopy surface topography measurements of post-CMP tungsten indicate that the roughness of the tungsten is independent of polish pressure and rotation rate. Pure mechanical abrasion is therefore an unlikely mechanism of material removal during CMP. Transmission electron microscopy images corroborate these results. The adhesion force between alumina and tungsten was measured in solution. The adhesive force increased with KIO3 concentration. Friction forces were measured in solution using lateral force microscopy. The friction force in buffered solutions was independent of KIO3 concentration. These results indicate that interactions other than purely mechanical interactions exist during CMP.

Platinum and palladium powders with average particle sizes in the submicron range have been synthesized at room temperature by hydrazine reduction of and , respectively, in glycols. Platinum powders contain spherical particles with a bimodal size distribution. Palladium powders also contain spherical particles, but the size distribution is narrow. The effect of both ammonia and hydrazine concentration on the size distribution and average size of palladium particles was investigated.

Six thermophysical properties of both solid and liquid zirconium measured using the high-temperature electrostatic levitator at the Jet Propulsion Laboratory are presented. These properties are density, thermal expansion coefficient, constant pressure heat capacity, hemispherical total emissivity, surface tension, and viscosity. For the first time, we report the densities and the thermal expansion coefficients of both the solid as well as liquid Zr over wide ranges of temperatures. Over the 1700–2300 K temperature span, the liquid density can be expressed as ρ1(T) = 6.24 × 103 – 0.29(T – Tm) kg/m3 with Tm = 2128 K, and the corresponding volume expansion coefficient as α1 = 4.6 × 10−5/K. Similarly, over the 1250–2100 K range, the measured density of the solid can be expressed as ρs(T) = 6.34 × 103 – 0.15(T – Tm), giving a volume expansion coefficient αs = 2.35 × 10−5/K. The constant pressure heat capacity of the liquid phase could be estimated as Cpl(T) = 39.72 – 7.42 × 10−3(T – Tm) J/(mol/K) if the hemispherical total emissivity of the liquid phase εT1 remains constant at 0.3 over the 1825–2200 K range. Over the 1400–2100 K temperature span, the hemispherical total emissivity of the solid phase could be rendered as εTs(T) = 0.29 – 9.91 × 103 (T – Tm). The measured surface tension and the viscosity of the molten zirconium over the 1850–2200 K range can be expressed as ς(T) = 1.459 × 103 – 0.244 (T – Tm) mN/m and as η(T) = 4.83 – 5.31 × 10−3(T – Tm) mPa s, respectively.

The in-plane thermal diffusivity of chemical-vapor-deposited diamond films was measured as a function of diamond-growth rate. The films, 0.1–0.4 mm thick, were prepared in microwave-plasma reactor at growth rates ranging from 1 to 10 μm/h. A modification of Ångstöm's method was used to perform the diffusivity measurements. The thermal conductivity calculated from the thermal diffusivity shows an inverse relationship with growth rate. Analyses of Raman spectra indicate that both the line shifts and the line widths of the diamond Raman peak are practically independent of the deposition rate, except for the specimen grown at the highest growth rate.

Oxidic zirconium films prepared by chemical deposition from aqueous medium on sulfonic acid terminated self-assembled monolayers attached to an oxidized silicon surface were investigated with scanning electron microscopy and atomic force microscopy. Bulk precipitate forms in the 4 mM Zr(SO4)2 · 4H2O, 0.4 N HCl deposition medium at 343 K after approximately 30 min. Precipitate particles (200 nm and larger) were found embedded in the oxidic zirconium film and adsorbed on top of the film; they could be washed off, but patches of the film were removed. Working with unstable deposition solutions, in which homogeneous nucleation occurs, leads to preparation-inherent flaws in the film.

An epitaxial BaTiO3 film with 290-nm thickness was prepared on a MgO(001) single-crystal substrate by radio-frequency magnetron sputter deposition. The structural characteristics of the film were studied as a function of temperature in in situ, real-time synchroton x-ray scattering experiments. We found that the as-grown film was strained at room temperature and tetragonally distorted with the c axis normal to the film surface. Interestingly, its lattice parameters were found to be expanded 1.28% and 0.64% in both the in-plane and the out-of-plane directions, respectively (i.e., biaxially), comparing to those of a bulk BaTiO3. More importantly, as it was heated to 600 °C, the tetragonal structure was kept up without the phase transition, which is usually observed in other epitaxial ferroelectric thin films.

The suitable conditions for growth of KGd(WO4)2 (KGW) and KGd1–xREx(WO4)2— RE = Nd, Er, Yb, Ho, Tm, Pr—by the top-seeded-solution-growth method, using K2W2O7 as solvent, are discussed. The relation between crystal size, mean growth rate, distribution coefficient of the substituting element, and the presence of macrodefects is analyzed. The optical absorption corresponding to the band-gap transition of KGW has been found to be temperature dependent; the absorption threshold energy changes from 34405 cm−1 at 300 K to 35330 cm−1 at 7 K. Narrow pre-edge absorption bands at about 32000 and 32600 cm−1 have been ascribed to Gd3+ intraconfigurational transitions. The photoluminescence of most RE3+ ions has been observed under ultraviolet (UV) excitation close to the absorption threshold of KGW. This suggests the contribution of charge transfer bands. In Pr-doped samples the presence of a minor concentration of Pr4+ could also contribute in this region. The irradiation with UV light does not introduce any significant coloration of our samples.

Amorphous ceramics with the chemical composition Si3B3N7 and SiBN3C were produced from single-source molecular precursors by polymerization and pyrolysis. The powder and fiber materials were investigated by means of energy filtering transmission electron microscopy. The intensity of elastically scattered electrons is recorded to calculate the pair distribution function of these ceramics. In the pair distribution function of Si3B3N7 three significant maxima at 0.144, 0.172, and 0.291 nm are clearly resolved and are assigned to the pair distances B–N, Si–N, and Si–Si (N–N), respectively, by comparison to crystalline materials. The predominant structural units of the ceramic are trigonal planar BN3 and tetrahedral SiN4 groups, which are close to their regular symmetry. The overall pair distribution function of SiBN3C is very similar to that of Si3B3N7; however, the maxima are broadened due to the incorporation of carbon into the network. High-resolution mapping of the elements Si, B, N, and C with electron spectroscopic imaging reveals a homogeneous distribution on a subnanometer scale without precipitation or separation of, for example, carbon-rich clusters. Similarly, elemental mapping of Si3B3N7 reveals a random distribution of the elements Si, B, and N at the same scale. Both new ceramics consist of an amorphous network with bonds and coordinations as preformed in the precursor.

Diffusion of water in oxides is modeled as resulting from the solution and diffusion of molecular water in the oxide. This dissolved water can react and exchange with the oxide network to form immobile OH groups and different hydrogen and oxygen isotopes in the oxide. The model agrees with many experiments on water diffusion in oxides. The activation energy for diffusion of water in oxides correlates with the structural openness of the oxide, suggesting that molecular water is the diffusing species.

Persistent spectral hole burning was observed in Eu3+-doped BaO–PbO–P2O5 glasses, and the dependence of hole properties on the glass composition was investigated in relation to the local structure surrounding the Eu3+ ions. The hole was burned on the 7F0 → 5D0 transition of the Eu3+ ions, the depth of which decreased with increasing PbO content, whereas the hole width increased. The hole was burned at 6 K, filled on increase in temperature, and erased above 120 K. Judd–Ofelt parameters and fluorescence line-narrowing spectra indicated that the symmetry of the Eu3+ site increases and the covalency of the Eu–O bond decreases with increasing PbO content.

The effect of mechanical deformation via high-energy ball milling on the structure of the Fe40Ni40P14B6 metallic glass was studied by means of x-ray diffactometry, transmission electron microscopy (TEM), and differential scanning calorimetry (DSC). After 5 h of milling, TEM observations indicated that some nanocrystallites with a diameter of about 6 nm precipitated from surface layers of the amorphous ribbons, whereas the bulk remained amorphous. When milling time was increased to 11 h, bulk crystallization occurred. The amorphous Fe40Ni40P14B6 alloy crystallized into a mixture of γ–(Fe, Ni) and (Fe, Ni)3(P, B). To understand the microstructural changes occurring in the amorphous ribbons before the onset of bulk crystallization, the isothermal crystallization behavior of as-deformed amorphous ribbons was studied. Compared with as-quenched amorphous ribbons, the local value of the Avrami exponent, derived from isothermal DSC data, increased from 3.5 to 4.1 for bulk crystallization. The thermal crystallization mechanism of deformed amorphous Fe40Ni40P14B6 ribbons changed from an eutectic-type reaction with simultaneous precipitation of γ–(Fe, Ni) and (Fe, Ni)3(P,B) from the amorphous matrix to a primary-type reaction with precipitation of α–Fe(P,B) preceding the formation of γ–(Fe,Ni) and (Fe,Ni)3(P,B). Our results suggest that several hours of mechanical milling cause surface crystallization and some atomic rearrangements in the amorphous alloy. The latter effect may be responsible for the observed primary-type reaction for crystallization of the deformed amorphous alloy

Magnetic and mechanical properties of Co-rich amorphous microwires of nominal compositions (Co1–xMnx)75Si10 B15 (0.08 < x < 0.11) and Co56.5Fe6.5Ni10B16Si11 with nearly zero magnetostriction constant have been studied. Drastic changes of the hysteresis loop with the decrease of x from rectangular to flat shape were observed at x < 0.1, while the Co56.5Fe6.5Ni10B16Si11 microwire showed rectangular hysteresis loops. Compositions with x ≥ 0.1 have small but positive magnetostriction constant while negative λs values have been observed at x ≤ 4 0.09, indicating rectangular character of the hysteresis loop in samples with nearly zero and even for small negative λs. External stress dependence of switching field, H*, showed an increase of H*; with s for samples with x = 0.11 and a decrease of H* with σ for x = 0.1. Besides, microwires of the same composition but with different dimensions showed different H*(σ) dependencies.