Microcompression tests were performed on the Al/Nb multilayers of incoherent interfaces with the layer thicknesses of 5 nm Al/5 nm Nb and 50 nm Al/50 nm Nb. The Al-Nb multilayers showed increase in strength as the layer thickness was reduced; the average flow stresses at 5% plastic strain from the 5 nm Al/5 nm Nb and 50 nm Al/50 nm Nb layer thickness specimens were determined to be 2.1 GPa and 1.4 GPa respectively. The results from this Al-Nb microcompression study were compared with those of the previous report on Cu-Nb multilayer microcompression results that indicated that the flow stresses of the Al-Nb multilayer are lower than those of Cu-Nb with the same bilayer spacing. The observed difference in strength was attributed to a potential difference in the interfacial strength of the two incoherent multilayer systems.

We have demonstrated resistance switching using polycrystalline HfO2 film with a Cu top electrode for nonvolatile memory applications and revealed the Cu diffusion into the HfO2 layer during the filament formation process. Resistive switching was clearly observed in the Cu/HfO2/Pt structure by performing a current–voltage measurement. The current step from a high-resistive state to a low-resistive state was of the order of 103–104 Ω, which provided a sufficient on/off ratio for use as a switching device. The filament formation process was investigated by employing hard x-ray photoelectron spectroscopy under bias operation. The application of a bias to the structure reduced the Cu2O state at the interface and the intensity ratio of Cu 2p3/2/Hf 3d5/2, providing evidence of Cu2O reduction and Cu diffusion into the HfO2 layer. These results also provide evidence that the resistance switching of the Cu/HfO2/Pt structure originates in a solid electrolyte (nanoionics model) containing Cu ions.

The dielectric properties and tunability with external magnetic and electric fields for LuFe2-xMnxO4 (0 ≤ x ≤ 1) are systematically studied. It was found that the dielectric loss, the ferrimagnetic Curie temperature, and the conductivity reduce with increasing Mn doping. One of the most important results is that the room temperature dielectric tunability with low magnetic and electric fields can be achieved in these samples. The analysis demonstrates that the electron transfer between Fe2+ and Fe3+ is efficiently suppressed with Mn doping and thus results in the decreases of the leaky conductivity and the dielectric loss. Furthermore, from the studies on the combination of impedance and modulus complex planes for the samples with different electrodes, the tunability is found to be more closely related to the extrinsic effect than the intrinsic bulk effect.

Although atomic layer deposition (ALD) has been used for many years as an industrial manufacturing method for microprocessors and displays, this versatile technique is finding increased use in the emerging fields of plasmonics and nanobiotechnology. In particular, ALD coatings can modify metallic surfaces to tune their optical and plasmonic properties, to protect them against unwanted oxidation and contamination, or to create biocompatible surfaces. Furthermore, ALD is unique among thin film deposition techniques in its ability to meet the processing demands for engineering nanoplasmonic devices, offering conformal deposition of dense and ultrathin films on high-aspect-ratio nanostructures at temperatures below 100 °C. In this review, we present key features of ALD and describe how it could benefit future applications in plasmonics, nanosciences, and biotechnology.

In this article, the binary-phased PbTe–Sb2Te3 nanopowders were synthesized via a hydro/solvo-thermal route to improve the thermoelectric properties of PbTe matrix material. The single-phased PbTe powders exhibit pure nanoparticles, but the binary-phased PbTe–Sb2Te3 powders have a mixed morphology composed of nanospheres and nanoribbons. Our results suggest that the thermal conductivity of the binary-phased PbTe–Sb2Te3 bulks can be reduced significantly and the Seebeck coefficient can be increased obviously, although the electrical conductivity can also be decreased sharply. Consequently, a large figure of merit 0.85 at 623 K can be achieved for 0.7PbTe–0.3Sb2Te3 bulk, which is enhanced by about one time as compared to that of the single-phased PbTe bulk. This large enhancement could be attributed to the lowered carrier concentration and the increased interface scattering in the binary-phased PbTe–Sb2Te3 materials with a mixed morphology.

A clickable surface was prepared using nanoporous SBA-15 support. Methylimidazolium, an ionic liquid, was immobilized on this surface through the click reaction. Detailed characterization using nitrogen adsorption, elemental analysis, x-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis showed that the ionic system was fixed inside the channels and the ordered porous structure remained stationary. Influence of this material on photoluminescence emission of 5-amino-4-hydroxy-7-sulfonaphthalene-2-sulfonate anion (H-acid) in aqueous solutions was evaluated. This click reaction product can be used effectively for H-acid removal from wastewater.

A review is given on the use of ion-beam-assisted deposition (IBAD) to the growth of films within the B–C–N system, both as monolithic and multilayer coatings. The films considered include elemental, binary, and ternary materials like pure carbon (diamond-like carbon), pure boron (B), boron nitrides (c‑BN, h‑BN, and BNx), boron carbides (B4C and BxC), carbon nitrides (CNx), and ternary BxCyNz. The use of non-reactive IBAD with argon ions and reactive IBAD with nitrogen ions is discussed in connection with control of the composition, physical and chemical sputtering, film density, internal stress, and promotion of metastable phases.

We developed a polyatomic cluster ion beam system for materials processing, and polyatomic clusters of materials such as alcohol and water were produced by an adiabatic expansion phenomenon. In this article, cluster formation is discussed using thermodynamics and fluid dynamics. To investigate the interactions of polyatomic cluster ions with solid surfaces, various kinds of substrates such as Si(100), SiO2, mica, polymethyl methacrylate, and metals were irradiated by ethanol, methanol, and water cluster ion beams. To be specific, chemical reactions between radicals of polyatomic molecules and surface Si atoms were investigated, and low-irradiation damage as well as high-rate sputtering was carried out on the Si(100) surfaces. Furthermore, materials processing methods including high-rate sputtering, surface modification, and micropatterning were demonstrated with ethanol and water cluster ion beams.

Chips produced by turning a commercial purity magnesium billet were cold compacted and then hot extruded at four different temperatures: 250, 300, 350, and 400 °C. Cast billets, of identical composition, were also extruded as reference material. Chip boundaries, visible even after 49:1 extrusion at 400 °C, were observed to suppress grain coarsening. Although 250 °C extruded chip-consolidated product showed early onset of yielding and lower ductility, fully dense material (extruded at 400 °C) had nearly 40% reduction in grain size with 22% higher yield strength and comparable ductility as that of the reference. The study highlights the role of densification and grain refinement on the compression behavior of chip consolidated specimens.

This article reports on microstructure and dielectric properties of Ba0.5Sr0.5Ti1−3y/2WyO3 ceramics. Dielectric peaks of the Ba0.5Sr0.5Ti1−3y/2WyO3 ceramics were markedly suppressed, broadened, and shifted to low temperature with increasing content of W. The limit of W incorporating into the barium strontium titanate (BST) lattice was y = 0.02. Two second phases (BaWO4 and Ba2Ti5O12) were formed above the solid solution limit of W in BST. The doping mechanism represents a new approach to develop microwave tunable materials. Dielectric properties of the Ba0.5Sr0.5Ti1−3y/2WyO3 ceramics could be optimized by the content of W. The sample with y = 0.05 had ε′ of 431, quality factor of 365 (at 2.111 GHz), and tunability of 11.5%, which makes a potential candidate for tunable microwave device applications in the wireless communication.

Tetra(4-dihydroxyborylphenyl)germanium as the tetrahedral units and 1,2,4,5-tetrahydroxybenzene as linkers were selected to form a crystalline porous aromatic framework, CPAF-13, with the planar five-membered BO2C2 ring in its structure by a dehydration reaction. The crystallinity of CPAF-13 was confirmed by x-ray diffraction analysis. The Ar sorption measurement on activated CPAF-13 results in a surface area of 417 m2/g, using Brunauer Emmett Teller model. CPAF-13 also shows a considerable adsorption capacity of H2.

We observed the formation of dominant shear bands in model ZrCuAl metallic glass (MG) nanowires (18-nm-long) in molecular dynamics simulations, which implies size-independent incipient plasticity in MG materials. The MG nanowires were prepared using the simulated casting technique to ensure proper relaxation of sample surfaces. Under uniaxial compression, shear bands initiate at the surfaces and lead to reduced icosahedral short-range order. The shear band formation is sensitive to sample thermal history, which calls for careful consideration of sample preparation effects in both experimental and numerical studies of size effect in MG samples.

Thin native oxide layers can dominate the mechanical properties of metallic thin films. However, to date there has been little quantification of how such overlayers affect yield and fracture during indentation in constrained film systems. To gain insight into such processes, electrical contact resistance was measured in situ during nanoindentation on constrained thin films of epitaxial Cr and polycrystalline Al, both possessing a native oxide overlayer. Measurements during loading of the films show both increases and decreases in current, which can then be used to distinguish between various sources of plasticity. Ex situ measurements of the oxide thickness are used to provide a starting point for elasticity simulations of stress in both systems. The results show that dislocation nucleation in the metal film can be differentiated from oxide fracture during indentation.

Polyaniline (PANI) microtubes were successfully synthesized by a simple way without using any templates. Their structure was characterized by scanning electron microscopy, transmission electron microscopy, x-ray diffraction, ultraviolet–visible absorption spectra, and Fourier transform infrared spectroscopy. The average length and diameter of the microtubes were about 12.0 and 3.0 μm, respectively. In addition, silver microrods were further prepared using the PANI microtubes as templates. Scanning electron microscopy, energy-dispersive x-ray spectra, x-ray diffraction, and ultraviolet–visible absorption spectra analyses were performed to characterize the structure of the sample. The results indicated the formation of silver microrods inside PANI microtubes. Moreover, the microwave absorption and electrical properties of PANI microtubes, PANI particles, and silver microrods were compared. It shows that the silver microrods coated with PANI have good microwave absorption and electrical properties, which can apply on electromagnetic interference shielding and microwave absorption materials.

The Zr65Al7.5Ni10Cu17.5 bulk metallic glasses were prepared by injection casting (casting temperature of 1100 °C) and in situ suction casting (casting temperature as high as 3000 °C). The strain-rate-dependent mechanical behaviors of the specimens were investigated under axial compression at room temperature over a wide strain rate range (1.6 × 10−5–1.6 × 10−1 s−1). The specimens prepared by injection casting exhibited negative strain rate sensitivity, i.e., the yield stress decreased with increasing strain rate. In contrast, no strain rate sensitivity was observed for the specimens prepared by in situ suction casting. The different strain rate sensitivities in the specimens prepared at different temperatures were probably caused by the diversities of the local atomic structures.