Bisethylacetoacetato Cu(II), referred to as Cu(etac)2, was synthesized and used as a novel metal-organic precursor to produce Cu films by PECVD processing. Cu(etac)2 is a nonfluoride compound that is solid at room temperature with reasonable volatility at 120–150 °C of 0.8 Torr. Effects of selected process variables on the characteristics of Cu film deposition were studied. Considered variables were plasma power, hydrogen flow rate, deposition time, substrate temperature, and precursor temperature. The process conditions to give Cu films of a high quality were determined. The electrical resistivity approached 2 μΩ · cm as the Cu film thickness became greater than 2500 Å. The conformality of the Cu film deposition by PECVD was sufficient to result in complete via-hole fillings of wafers patterned for 256 Mb DRAM.

The enthalpies of formation and the partial molar enthalpies of oxidation of polycrystalline LnBa2Cu3Oy (Ln = Pr, Nd, Eu, Gd, Dy, Ho, Tm) and Y1−xPrxBa2Cu3Oy (x = 0.0, 0.1, 0.2, 0.5, 0.8, 0.9, 1.0) have been determined at 298 K by drop-solution calorimetry. The thermodynamic characteristics of Pr123 follow the trends of the trivalent-ion-based Ln123 compounds. The thermodynamic data for the (Y,Pr)123 solid solutions show nonideal solution behavior, but no x-dependent valence instability. The superconducting critical temperatures and the enthalpies of oxidation of the (Y,Pr)123 solid solutions are linearly related.

We report on the properties and characterization of SrBi2Ta2O9 (SBT, or Y − 1) thin film capacitors for ferroelectric random access memory (FERAM) applications. The films were prepared by spin-coating from carboxylate precursors. The remanent polarization (Pr) was 5−6 μC/cm2 and the coercive field was ∼55 kV/cm. Excellent fatigue endurance was observed up to 1011 cycles. Auger analysis indicates bismuth diffusion through the Pt electrode after capacitor anneal which might require excess Bi in the precursor solution for stoichiometry control. No detectable amount of α emission was found from SBT films, which reduces the possibility of soft error when used in the memory devices.

Ball milling is a technique used extensively in metallic powders to obtain adequated properties for their applications. In this study we show that this technique is also useful for preparing organic molecular alloys. Pentaglycerin/Pentaerythritol alloys have been obtained mechanically at room temperature. Calorimetric and crystallographic characterizations establish that the mechanically obtained alloys have the same solid crystalline structure and transform to the plastic phase as the conventionally prepared alloys from the melt of the pure compounds.

Time of flight (TOF) spectroscopic measurements are used to diagnose the laser-generated plume of ceramic NdBa2Cu3Ox targets. We have been able to directly correlate the laser-deposited films' properties such as superconductivity, crystallinity, and orientation with plasma properties. Study of the TOF spectra shows that at laser fluences greater than 3 J/cm2 the plume become Nd-rich, and this leads to a low Tc in the deposited film. We have also shown the effect of target density on the energy of the plume species, and through energy considerations we have explained the observed change in the crystalline orientation of films from c- to a-orientation with increasing the target density. Finally, we have examined the oxidation mechanism of NdBa2Cu3Ox thin films, and have shown that highly energetic atomic oxygens have a prevailing role in oxidizing our laser-deposited thin films.

The ytrrium solubility in Ba–Cu–O solvent with a Ba to Cu ratio of 3 to 5 was investigated under different oxygen partial pressure [P(O2) = 2, 21, 100%]. A small amount of the solution was taken out by dipping thermally equilibrated MgO single crystals, and compositions of these specimens were analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES). The measurements were performed for the samples prepared in the temperature range from approximately 950 °C up to 1100 °C. The peritectic temperature of YBa2Cu3O72x (Y123) decreased with decreasing oxygen partial pressure. On the other hand, the Y123 liquidus lines do not show remarkable oxygen partial pressure dependency. Accordingly, the yttrium solubility at the peritectic temperature of Y123 under P(O2) = 100% was larger than those for the other conditions [P(O2) = 2% and 21%]. Assuming a regular solution, expressions for the solubility and the enthalpy of dissolution of Y123 and Y2BaCuO5 (Y211) were derived from classical thermodynamic calculations and found to be 289 kJ/mol at P(O2) = 0.02, 239 kJ/mol at P(O2) = 0.21 atm, 206 kJ/mol at P(O2) = 1 atm for Y123, and 105 kJ/mol at P(O2) = 0.02 atm, 88.0 kJ/mol at P(O2) = 0.21 atm, and 88.4 kJ/mol at P(O2) = 1 atm for Y211. Furthermore, the Jackson α factor of Y123 was estimated to be about 20, confirming a faceted growth nature of this crystal.

The magnetic anisotropy of rare-earth substituted 2212 materials (Bi2Sr2Ca0.8RE0.2Cu2Ox with RE = Gd, Dy, Ho, Er) is put into evidence. Superconducting powder dispersed in epoxy resin is oriented under an external magnetic field (4 T) in a direction that depends on the nature of the rare-earth used in the substitution. Both directions of observation (parallel or perpendicular to the field) were investigated. Splitting of (00l) peaks is neatly observed and discussed.

We have used pulsed organometallic beam epitaxy (POMBE) to simultaneously deposit â- and ĉ-axis oriented Y1Ba2Cu3O7−x (YBCO) thin films at arbitrary locations on LaAlO3(100) substrates. Using photolithography and ion milling, several types of â-ĉ weak links have been fabricated at the boundary between the two films. The current-voltage (I-V) characteristics show a flux flow type behavior. The resistive transitions are broad and the critical current density is low, indicating weak coupling across these boundaries. With magnetic field applied parallel to the grain boundary plane, nonhysteretic I-V curves are obtained and the critical current goes to zero at an applied magnetic field of ∼7500 G.

To clarify the effect of undercooling on the crystal growth of Y-123, the growth rate was measured with different undercoolings. The growth rate of the {100} face shows a quadratic dependence of undercooling, while that of the {001} face shows a linear dependence in the sample with nominal 123 composition. In the case with 211-rich composition, the growth rate of each face was larger than that compared with nominal 123 composition since the mass flux from 211 particle for peritectic reaction becomes large. Addition of excess 211 alters the undercooling dependence of Ra from quadratic to linear. It is considered that the entrapment of 211 particles into 123 crystals supplies step sources beside screw dislocations. The growth rate of the {001} face is larger than that of the {100} face up to 26° of undercooling.

The effect of sintering periods for monocore (Bi, Pb)2Sr2Ca2Cu3O10+x (Bi-2223) tapes on microstructure and critical current density (Jc) have been studied. The results show that long sintering periods (of duration ≥100 h) give better grain growth, but greater misalignment. Prolonged sintering also necessitates the increase in porosity of the core due to random grain growth, increasing the chance of penetrating into the silver matrix and oxide core interface. Critical currents for long sintering periods are found to be lower in comparison with those obtained for slightly shorter sintering periods. The increase in frequency of intermediate cold uniaxial pressing between sintering periods assists grain alignment. However, when the sintering period is further reduced by increasing the frequency of intermediate deformation, it is found that microcracks are unable to heal as there is not enough time for grain regrowth. The tapes made using “three-to-four-sinter-period” (each period ∼60 h) show superior electrical transport properties which are attributable to the fact that their oxide core is more dense and better aligned relative to the “two-sinter-period” (each period ≥100 h) tapes and contain less cracks relative to the “five-to-six-sinter-period” (each period ∼40 h) tapes.

To reduce grain boundary weak links due to large-angle grain orientation mismatch, bulk (thick film) EuBa2Cu3O7−δ high-Tc superconductor specimens were biaxially aligned by a mechanical force such that their [001] axes were perpendicular to the specimen surfaces and by a magnetic force so as to orient their [010] axes to lie parallel to the magnetic field direction in the specimen plane. We describe here the characterization of such EuBa2Cu3O7−δ thick films by φ-circle XRD scans of (013) reflections, demonstrating a high degree (33%) of c-axis alignment with FWHM of <5° and approximately Gaussian distributions of a, b-axis alignment with a FWHM of 47°. The formation of “granular single crystals”, toward which this work is a further advance, can be seen as establishing a new paradigm in ceramics science.

Y1Ba2Cu307−x (Y123) crystals were grown by two different methods, the constant undercooling solidification and the continual cooling method, with top seeding by Sm123 seed crystals in order to investigate a relationship between undercooling (ΔT) and a growth rate (R). The crystals of Y123 with a sharp faceted interface, which consisted of {100} and {001} faces, grew epitaxially from the seed. It was found that the growth rates of {100} face (Ra) and that of {001} face (Rc) showed an increasing trend with increasing ΔT, and Rc was faster than Ra within these experimental conditions, ΔT < 20 K. The relation between R and ΔT follows the parabolic equation, viz. Ra ∝ ΔT1.9 and Rc ∝ ΔT1.3 for {100} and {001} faces, respectively. The simulated crystal size using the R and ΔT relations obtained from the constant undercooling method showed good agreement with experimental data by the continual cooling.

Zn-doped YBa2Cu3O6+δ (YBCO) single crystals were fabricated by the solute-rich liquid-crystal pulling (SRL-CP) method. The Zn content of x ranged from 0.0035–0.029 and almost uniformly distributed in YBa2(Cu1−xZnx)3O6+δ. There is a nearly linear relationship between the added Zn content in the liquid and the analyzed Zn content in the liquid/in the crystal. When the added Zn content Cl was 1.086 at. %, decreasing of growth temperature led to increasing growth rate. However, growth temperature had no obvious effect on the doped Zn content in the crystal Cs, the Zn content in the flux Cl, and the effective distribution ratio of k′. In addition, growth spirals on the grown crystal surface were observed by atomic force microscopy (AFM). X-ray Laue pattern and RBS measurements are indicative of good crystallinity of YBa2(Cu1−xZnx)3O6+δ. Critical temperatures of Tc changed from 89 to 57 K when the Zn content x ranged 0.0035 to 0.029 after appropriate oxygenation.

The debinding process of injection-molded compacts of Fe–8Ni mixed powders, containing binders of different ratios of polymers to wax, was investigated. The effect of binder compositions and debinding conditions on the sinterability of the compacts were also studied. Distortions produced in the debinding processes of the compacts were minimized for the case where a ratio of polymer to the total binder contents was 0.35. In the case of the compacts debound in air, sintered densities increased by increasing the debinding temperature up to 350 °C, then decreased sharply for higher debinding temperatures. In the compacts debound in N2, sintered densities were almost independent of the debinding temperature. The sinterability of the compacts debound in N2 was inferior to that debound in air.

X-ray diffraction and temperature dependent (5 K–380 K) magnetic measurements have been carried out in INCONEL 718 superalloy before and after high temperature aging treatments. (INCONEL is a trademark of the INCO family of companies.) The nominal composition of this alloy is Ni (52.5%), Cr (19.0%), Fe (18.5%), Nb (5.1%), Mo (3.0%), Ti (0.9%), Al (0.5%), Cu (0.15%), and C (0.08%), and it yields an x-ray diffraction pattern consisting of a fcc phase with α = 3.5987 (3) Å and an orthorhombic phase associated with δ-Ni3Nb. It is concluded that the fcc pattern is due to both the γ austenitic phase and γ′ Ni3(Al, Ti) phase of alloy 718. The standard annealing and aging treatment carried out in air at temperatures between 621 and 982 °C produces surface oxides (Cr, Fe)2O3 and FeNbO4 (which are easily removed by etching and polishing) and contracts the lattice. Magnetic measurements show a distinct phase transition at Tc = 14 K, which has been attributed to the γ′-Ni3(Al, Ti) phase by the process of elimination and by observing that it has most of the characteristics of the weak itinerant ferromagnet Ni74.5Al25.5. This transition may have some effects on the cryogenic applications of this alloy.

The roles of metallic droplets, which generated from the cathodic arc spot holes in the technology of Cathodic Arc Plasma Deposition (CAPD), are investigated by SEM, TEM, image analysis apparatus, and electronic probe energy spectrum analysis. The results show that though many papers in recent years are devoted to eliminate them, the metallic droplets, including the macrodroplets, have many important positive roles in the preparation of alloy films: they are the main factor to transfer the original composition of alloy cathodic target to the alloy thick films; they preserve the high deposition rate of CAPD to form the basic characteristics of the microstructure and to affect the pore ratios of the films; they also preserve the high melting point elements in the alloy films, and therefore preserve the corrosion resistance of the alloy in the films. The macrodroplets can be eliminated by raising the substrate temperature properly, which is permitted in some cases, such as depositing alloy films onto middle carbon steel as an anticorrosion system, etc.

The effects of plasma cycle and TiO2 doping on sintering kinetics during plasma activated sintering (PAS) of γ−Al2O3 have been studied in the temperature range of 1473–1823 K. Multiple plasma cycle leads to higher densification. Also, TiO2 doping enhances the sintering kinetics during PAS. In TiO2 doped specimens, near full density was obtained at 1673 K in less than 6 min using multiple plasma cycle. It is suggested that the dielectric properties of a material are critical for the success of the PAS process.

The effect of substrate bias voltage on the properties of arc ion-plated TiN films onto high speed steels has been investigated. The high density structure with a large crystallite size grew at the high bias voltage. TiN films deposited by higher bias exhibited strong preferential (111) orientation from XRD. The internal stress of TiN films increased at first with increasing substrate bias voltage; however, it decreased as the bias voltage increased over 100 V. The coating adhesion measured by the scratch tester increased with increasing bias voltage, and this is coupled with a cohesion of films. Cutting performance of TiN coated drills, which increased markedly with increasing substrate bias, has been studied in relation to the physical and chemical properties of deposited films.

α–ZrP whiskers have been prepared from ZrCl4 + PCl3 + H2 + Ar gas mixtures at 1050–1250 °C using the mixed metal impurity-activated chemical vapor deposition process. The growth conditions, morphology, growth mechanism, and some properties were examined. The mixed impurities of Si + Pt and Si + Pd were very effective for the ZrP whisker growth with 8–12 mm (avg. 10 mm) long whiskers being obtained at 1300 °C for 1 h. The growth direction of the whiskers having hexagonal and square cross sections were along the c-axis and a-axis, respectively. The whiskers were very stable to an 80 min immersion in a concentrated HCl solution.

Powder x-ray diffraction (XRD) and Raman evidence are presented for the formation of crystalline diamond in the “hydrothermal” pressure-temperature regime 1–5 kbars, <1000 °C. Two different methods appear to enable diamond to nucleate and grow. One—a Low Pressure Solid-State Source (LPSSS) route—utilizes special solid precursors, especially low temperature glassy carbon (GC-500), with very fine diamond seeds in sealed gold capsules with H2O at, say, 800 °C and 1 kbar. The other includes pyrolysis of highly selected organic solid/liquid precursors (halogenated aliphatics such as iodoform) onto similar diamond seeds. In all the cases, powder x-ray diffraction evidence shows a marked increase of the diamond XRD peaks, likewise the Raman spectrum shows a strong increase of the 1331 cm−1 line. However, the crystals apparently are too small to be seen in the SEM. TEM diffraction data, on the other hand, seem to lend support to the possibility of all the grown diamonds being very small.