A promising approach to control Pb stoichiometry during crystallization of sol-gel-derived lead zirconate titanate (PZT) layers is presented. Pyrolyzed layers were encapsulated in a quartz ampoule containing PbZrO3 powder and crystallized in a lamp furnace. For moderate heating rates, the PbO ambient created by the powder resulted in a pronounced sharpening of the preferential (111) texture, while the remanent polarisation Pr increased by 50% compared to nonencapsulated samples. A significant reduction of the coercive field was seen for layers crystallized under PbO ambient, reflected in a lowering of the switching voltage by 0.5 V compared to standard hotplate crystallized films. The results highlighted the key role of Pb stoichiometry control for further lowering the switching voltage of PZT films.

Due to growth tensile stress, which evolves in diamond films during deposition, thick diamond films are easily cracked. In this study we successfully prevented growth cracks by introducing thermal compressive stress with step-down control of deposition temperatures during growth. Three deposition temperature drops of 10 °C each during deposition enabled us to successfully synthesize crack-free four-inch diamond wafers several hundred micrometers in thickness. This method is very simple and may be applicable to coating of films of various materials different from those of substrates.

The potential of the newly developed Sn–9Zn solder paste as a lead-free solder, especially focusing on the stability at high temperature, was examined. The initial interface strength between Sn–9Zn and Cu, about 50 MPa by the tensile test, is higher than other interfaces such as Sn–37Pb/Cu. While the Sn–9Zn/Cu interface maintains the high strength level after heat exposure at 125 °C, the heat exposure at 150 °C degrades strength seriously. The degradation at 150 °C is caused by dissipation and by disruption of the Cu–Zn reaction layer at the interface. Where the Cu–Zn layer is eroded to form a whole, Sn directly reacts with a Cu substrate to form a thick Sn–Cu reaction region. Such an interfacial morphology change causes the serious degradation. With the Ni/Pd/Au coating on a Cu substrate, the interface becomes much stronger than the direct interface. Even after heat exposure at 150 °C, strength degradation is not so significant. Zn segregates into the coating layer. During high-temperature exposure, Ni and Pd diffuse each other. Zn also diffuses into the coating layer to form compounds, and as a result, a depleted zone of Zn is formed in the solder close to the interface.

Li–ZrSiO4 was synthesized by the sol-gel method. Reactions were performed with different Li:Zr molar ratios: 1, 3, 5, and 6. Cell parameters changed as follows: a0 decreased and c0 increased as the Li:Zr molar ratio increased. The x-ray photoelectron spectroscopy analysis showed two kinds of oxygen atoms. The first one was attributed to ZrSiO4 oxygens. The second one was attributed to Li–O bonds. All these results were supported by a theoretical analysis. It was concluded that lithium atoms were held in interstitial positions of the ZrSiO4 structure.

We investigated the atomic structure, electrical, and infrared range optical properties of diamondlike carbon (DLC) films containing alloy atoms (Cu, Ti, or Si) prepared by pulsed laser deposition. Radial distribution function (RDF) analysis of these films showed that they are largely sp3 bonded. Both pure DLC and DLC + Cu films form a Schottky barrier with the measuring probe, whereas DLC + Ti films behave like a linear resistor. Pure DLC films and those containing Cu exhibit p-type conduction, and those containing Ti and Si have n-type conduction. Photon-induced conduction is observed for pure DLC, and the mechanism is discussed in terms of low-density gap states of highly tetrahedral DLC. Our results are consistent with relative absence of gap states in pure DLC, in accordance with theoretical prediction by Drabold et al.37 Temperature dependence of conductivity of DLC + Cu shows a behavior σ ∞ exp(−B/T1/2), instead of the T−1/4 law (Mott–Davis law). Contributions from band-to-band transitions, free carriers, and phonons to the emissivity spectrum are clearly identified in pure DLC films. The amorphous state introduces a large contribution from localized states. Incorporation of a small amount of Si in the DLC does not change the general feature of emissivity spectrum but enhances the contribution from the localized states. Cu and Ti both enhance the free carrier and the localized state contributions and make the films a black body.

The band offsets and band gap are the most important parameters that determine the electrical and optical behavior of a heterojunction. In situ scanning tunneling spectroscopy was employed to measure the valence-band offset of strained Si1−xGex-on-Si (100) for the first time. The valence-band offsets of the strained Si0.77Ge0.23 and Si0.59Ge0.41 on Si(100) were found to be 0.21 and 0.36 eV, respectively. The results were in good agreement with theory and with results from other experimental methods. Due to band bending and surface states, it was difficult to determine the conduction band edge at the interface of the Si1−xGex/Si exactly but we found that the conduction band offset is much smaller than the valence-band offset.

The phase diagram of the Sm2O3–CuO system was investigated by the combination of the differential thermal analysis and the quench method. The results showed that Sm2CuO4 incongruently melts at about 1220 °C, and that the solid Sm2CuO4 exists in equilibrium with the liquid consisting of 81–95 mol% CuO in the range of 1060–1220 °C. On the basis of the phase diagram, Sm2−xCexCuO4 single crystals were grown by the traveling solvent floating zone method. The crystal structure [space group I4/mmm, a = 3.917(1), c 4 11.899(2) Å] has been refined using single-crystal x-ray diffraction data with a precision corresponding to an R index of 0.02.

Using an interfacial force microscope, the measured elastic response of 100-nm-thick Au films was found to be strongly correlated with the films' stress state and thermal history. Large, reversible variations (2×) of indentation modulus were recorded as a function of applied stress. Low-temperature annealing caused permanent changes in the films' measured elastic properties. The measured elastic response was also found to vary in close proximity to grain boundaries in thin films and near surface steps on single-crystal surfaces. These results demonstrate a complex interdependence of stress state, defect structure, and elastic properties in thin metallic films.

Tin oxide films were deposited on amorphous SiO2/Si and Si (100) substrates by ion-assisted deposition (IAD) at various ion beam potentials (VI) at room temperature and a working pressure of 8 × 10−5 torr. The structural and chemical properties of the as-grown tin oxide films were investigated to determine the effects of the oxygen ion/atom arrival ratio (Ri). X-ray diffraction patterns indicated that the as-grown films with different average energy per atom (Eave) showed different growth directions. The as-grown films with oxygen/Sn ratio (NO/NSn) of 2.03 and 2.02 had preferred orientation of (101) and (002), respectively. In addition, the as-grown film with low Ri was amorphous. Comparison of the observed d spacings with those for standard SnO2 samples, indicated that the crystalline as-grown films had compressive and tensile stress depending on Eave. In transmission electron microscopy analysis, a buffer layer of amorphous tin oxide was observed at the interface between the substrate and the film, and the crystalline grains were grown on this buffer layer. The crystalline grains were arranged in large spherical clusters, and this shape directly affected surface roughness. Rutherford backscattering spectroscopy spectra showed that the tin oxide thin films were inhomogeneous. The density of films decreased and the porosity and oxygen trapped in the films increased with increasing Ri. The densest film had about 6% porosity.

Structural and ferromagnetic transitions in shape memory Ni–Mn–Ga alloys and their martensitic structure and microstructure were found to be strongly influenced by rapid quenching from the liquid state and by subsequent aging. Detailed calorimetric and magnetic measurements, dynamic mechanical analysis, and transmission electron microscopy observations were performed to characterize the transformation behavior of thin ribbons compared to the bulk materials. The rapid quenching caused the decrease of the ferromagnetic, martensitic, and premartensitic transformation temperatures, as well as of the saturation magnetization, while the subsequent annealing brought about an increase of the depressed values. This influence was attributed to quenched-in short-range chemical disorder within sublattices, the ordering being improved by a vacancy migration mechanism upon subsequent annealing.

Phase-selective growth of TlBa2Ca2Cu3O9−x films is greatly enhanced by annealing chemical vapor deposition derived BaCaCuO(F) precursor films in the presence of TlF. Nucleation of superconducting phases (≥840 °C under O2) progresses in the order 2212 → 2223 → 1212 → 1223. Annealing at 855 °C results in well-defined platelet grains, a significant number of which are a-axis oriented. Residual fluoride is not detectable at any stage of the annealing process. Thin films synthesized by TlF annealing differ markedly from films processed in the presence of Tl2O3 with Tc = 103 K and Jc > 105 A/cm2 (5 K, 4.5 T).

A novel two-step metalorganic chemical vapor deposition process was used in this study to prepare Sr1−xBaxNb2O6 (SBN) thin films. Two thin layers of single-phase SrNb2O6 and BaNb2O6 were deposited alternately on a silicon substrate, and the solid solution of SBN was obtained by high-temperature annealing. The stoichiometry control of the SrNb2O6 and the BaNb2O6 thin films was achieved through deposition process control, according to the evaporation characteristics of double metal alkoxide. The evaporation behavior of double metal alkoxide precursors SrNb2(1-OC4H9)12 and BaNb2(1-OC4H9)12 was studied, and the results were compared with the evaporation of single alkoxide Nb(1-OC4H9)5.

The martensitic transformation behavior of FeMnGe alloy (0–6 wt% Ge) was investigated by resistivity and dilation methods. Ge depresses the martensitic transformation of FeMn alloy. The effect of Ge on starting temperature of martensitic transformation (Ms) temperature of FeMn alloy is −12 K/wt% Ge. Comparing Ge (4s24p2) with Si (3s23p2) and Al (3S23P1), which have similar outer shells of electrons, we found that their effects on the Ms of FeMn alloy are completely different. The result suggests that the outer shell of electron is not the main factor governing the Ms temperature of FeMn alloy, although it is essential in the alloy's antiferromagnetic transition.

This article, Part II in a series, reports on the grain refining performance of the Al–Ti–C alloys produced by reactive synthesis. Grain refinement was tested as a function of the following parameters in the reaction synthesis process: Ti content, Ti/C ratio, and cooling rate after the reaction. The grain refining performance of the alloys in the as-synthesized condition was limited due to either a shortage of TiC particles or an insufficient amount of aluminum matrix. Dilution of the alloys to a nominal composition of 3 wt% Ti, followed by extrusion improved the grain refinement to the level of commercially available Al–Ti–C grain refining alloys. A prerequisite for successful secondary processing is that the conversion of carbon is completed in the reaction synthesis; otherwise Al4C3 is formed rather than TiC.

Phase stability and transformations of the icosahedral phase (I-phase) in a 41.5Zr41.5Ti17Ni alloy were investigated using melt-spun ribbons and arc-melted bulk samples. A perfect I-phase can be formed directly from liquid through the melt-spinning technique. The I-phase formed in the ribbon is thermodynamically stable and transforms to W-phase, a 1/1 rational approximant above 565 °C. Formation of the perfect I-phase during annealing treatment of the arc-melted sample is very sluggish. Various types of approximants exist as intermediate states for the transformation of crystalline phases to a perfect I-phase.

Small additions of Hf to directionally solidified NiAl–Cr(Mo) eutectic resulted in precipitation of a high density of Heusler phase Ni2AlHf along with fine G-phase Ni16Hf6Si7. The Heusler phase was mainly located on the grain boundary region. The fine G-phase formed in the presence of Si, which was a contamination resulting from contact with ceramic shell molds during directional solidification of the alloy. These fine G-phases were cuboidal in shape and coherent with the NiAl matrix. After hot isostatic pressing and aging treatment, the fine G-phases completely disappeared. The density of the Heusler phase was partially reduced, and the Heusler particles precipitated preferentially on the NiAl/Cr(Mo) interfaces and grain boundaries of the NiAl matrix. Some Heusler particles precipitated locally within the NiAl matrix, and small amounts of them precipitated within the Cr(Mo) phase. The structures of the NiAl/Ni2AlHf and NiAl/Ni16Hf6Si7 interfaces were investigated by high-resolution electron microscopy. The habit plane of the fine G-phase was {001}NiAl. This result was in good agreement with calculation based on the linear elastic theory. The misfit dislocation network on the NiAl/Ni2AlHf (110) interface was calculated from the O-lattice model and compared with the observation, which showed good agreement.

A large, single-grain Nd–Ba–Cu–O (NdBCO) composite consisting of superconducting NdBa2Cu3O7-δ containing nonsuperconducting Nd4Ba2Cu2O10 phase inclusions was fabricated up to 2 cm in diameter using a top-seeded melt-textured growth technique. A MgO single-crystal seed was used to provide a heterogeneous nucleation site at the center of a presintered pellet heated above its peritectic temperature and cooled continuously in a conventional tube furnace in reduced oxygen partial pressure. This process produces individual grains with the c axis oriented at ≈10° to the seed surface which, from vibrating-sample magnetization measurements, exhibit a pronounced peak effect in their magnetic moment over a wide temperature range (50–90 K) when the supercurrent flows in the a-b planes. A very high irreversibility field (>9 T at 77 K) is also observed in these grains for field applied both perpendicular and parallel to the crystallographic c axis which is significantly greater than that observed in good-quality melt-processed Y–Ba–Cu–O. These results underline the potential of NdBCO for high-field engineering applications.

Photoluminescence (PL) and photo-induced-current transient spectroscopy measurements on As-doped CdTe/Cd0.96Zn0.04Te heterostructures grown by molecular beam epitaxy were carried out to investigate the optical properties and the annealing effects on the deep levels. The temperature dependence of the PL spectra showed that the luminescence intensity of the exciton peak related to the neutral acceptors (A°, X) decreased with increasing measurement temperature and that the activation energy of the (A°, X) peak for the As-doped CdTe epilayer was 7 meV. Five hole-trap peaks appeared for the annealed As-doped CdTe/Cd0.96Zn0.04Te heterostructure. Two of these peaks, denoted by H1 and H2, might be related to extrinsic impurities, and the other three peaks, represented by H3, H4, and H5, might be attributed to intrinsic impurities. These results can help improve understanding for the application of As-doped CdTe/Cd0.96Zn0.04Te heterostructures in optoelectronic devices.

The Taylor–Ulitovski technique was employed for fabrication of tiny ferromagnetic amorphous and nanocrystalline metallic wires covered by an insulating glass coating with magnetic properties of great technological interest. A single and large Barkhausen jump was observed for microwires with positive magnetostriction. Negative magnetostriction microwires exhibited almost unhysteretic behavior with an easy axis transverse to the wire axis. Enhanced magnetic softness (initial permeability, μι, up to 14000) and giant magneto impedance (GMI) effect (up to 140% at 10 MHz) was observed in amorphous CoMnSiB microwires with nearly zero magnetostriction after adequate heat treatment. Large sensitivity of GMI and magnetic characteristics on external tensile stresses was observed. Upon heat treatment, FeSiBCuNb amorphous microwires devitrificated into a nanocrystalline structure with enhanced magnetic softness. The magnetic bistability was observed even after the second crystallization process (increase of switching field by more than 2 orders of magnitude up to 5.5 kA/m). Hard magnetic materials were obtained as a result of decomposition of metastable phases in Co–Ni–Cu and Fe–Ni–Cu microwires fabricated by Taylor–Ulitovski technique when the coercivity increased up to 60 kA/m. A magnetic sensor based on the magnetic bistability was designed.

Al/Al2O3 composites were fabricated by a displacement reaction between SiO2 and molten Al. In this study, fabrication of Al/Al2O3 composites was attempted by means of reactive infiltration to provide variation of their mechanical properties. SiO2 preforms having various porosities and pore size distributions were prepared by sintering the powder at different temperatures between 1273 and 1723 K. Molten Al was infiltrated at 1373 K without application of pressure. Infiltration kinetics were studied and the microstructures of the composite bodies were observed by means of scanning electron microscopy (with energy dispersive x-ray microanalysis), wave dispersive x-ray microanalysis, and x-ray diffractions. The infiltrated specimens were mainly composed of Al and α–Al2O3 phases, and the Si content was less than 5 at.%. Volume fraction of Al phase in the composite bodies was not altered very much with the porosities of the SiO2 preforms because of the difficulty in filling out the entire pore space. Properties and microstructures of Al/Al2O3 composites, however, were dependent on the sintering temperature of the SiO2 preforms. In the case of low sintering temperature, a thick Al channel existed, which deformed upon compression. In the case of high sintering temperature, the microstructure became homogeneous and had thinner Al channels. The composite bodies became brittle. The deformation behavior was shown to be changed from ductile to brittle as an increase of the sintering temperature of the preforms.