In this article, scanning nonlinear dielectric microscopy (SNDM) with atomic resolution is reviewed. First, experimental results on the detection of ferroelectric domains are shown following a presentation about the theory and principle of SNDM. Next, a three-dimensional (3D) type of SNDM for measuring the 3D distribution of ferroelectric polarization and noncontact scanning nonlinear dielectric microscopy (NC-SNDM) are proposed. Using NC-SNDM under ultrahigh vacuum conditions, we clearly resolve the electric dipole moment distribution of Si atoms on a Si(111)7 × 7 surface. We also succeeded to resolve a fullerene (C60) molecule. Since the technique is applicable not only to semiconductors but also to both polar and non-polar dielectric materials, SrTiO3 and TiO2 surfaces were observed by NC-SNDM. Finally, we characterize an ultrahigh-density ferroelectric data storage system using SNDM as a pickup device and a congruent lithium tantalate single crystal as a ferroelectric recording medium.

An array of 32 sensor elements with single-walled carbon nanotubes (SWCNTs) as the sensing medium has been fabricated. The microfabrication approach used allows reduction of the chip size and increases the number of sensor elements in a chip and is amenable for large wafer scale-up. The sensor array chip is designed as an electronic nose for use with the aid of a pattern recognition algorithm. The sensor chips were tested for NO2 sensing and interfering effects from humidity and a background of chlorine. The results indicate that NO2 can be detected at low concentration levels of 0.5 ppm in the presence of chlorine at 30 times higher concentrations. The sensor response is affected by humidity, which implies that the training data set for NO2 detection needs to be generated for multiple humidity levels for interpolation purposes during field use.

Carbon nanocoils (CNCs) with diameter from 100 to 150 nm have been synthesized by catalytic decomposition of acetylene at 700 °C using Fe–Sn–O catalyst film prepared by a spin-coating method. The CNCs are much smaller in diameter than those synthesized using the catalysts prepared by a sol-gel method and a solution-dipping method. It is found that catalyst films with different morphologies are obtained by changing the spin-coating times, which lead to the formation of different multilayer carbon nanostructures, including CNCs/carbon layer/vertically aligned carbon nanotubes sandwich-like structures, and CNCs/carbon double-layer structures. Based on the experimental results, the growth mechanism of the multilayer carbon nanostructures has been proposed.

The size dependence of the lattice parameter of nanosolids has extensively been studied because lattice strain engineering is important in controlling the physical properties of nanowires (NWs), such as band gap, carrier transport, mechanical strength, etc. We have investigated the size-dependent lattice behavior of microstructure-controlled Sn NWs with radii of 7–35 nm. The NW microstructures were controlled as single-crystal, granular, and bamboo structures in the longitudinal direction. Results showed that the a-axis lattice parameter in the [100]-longitudinal direction of NWs can be controlled within 1% by varying the wire microstructure for the same wire radius because it is strongly dependent on the microstructure and the wire radius. Moreover, as the randomness of the grain orientation in the microstructure-controlled NWs increases, by which the anisotropy of surface stress is effectively reduced, the lattice strain of the NW can be compressive or tensile as a function of the wire radius. The longitudinal lattice parameters of microstructure-controlled Sn NWs can be tailored by reducing the effective anisotropy of surface stresses under a dimension confinement in the nanometer scale.

We report the low-temperature synthesis and characterization of polyvinylpyrrolidone (PVP)-capped FeAu magneto-plasmonic multifunctional nanoparticles by a one-step nanoemulsion process. The Fourier transform infrared spectroscopy study proves the PVP coating on the surface of the resultant FeAu nanoparticles, whereas the structural, magnetic, and optical analysis illustrates the fusion of iron and gold into one single nanostructure showing the nanoparticle shape and a tight size distribution with an average size of 11.3 nm, followed by the growth habit compared to other relevant nanoparticles. Moreover, the PVP-capped FeAu nanoparticles manifest soft ferromagnetic behavior with a small coercivity of ∼40 Oe at room temperature. The corresponding magnetic hysteresis curves were elucidated by modified bi-phase Langevin equations, which were reasonably interpreted with the binary particle size distribution. The nanoparticles reveal a well-defined surface plasmon resonance band at ∼546 nm and a visual demonstration shows the magnetic separability of all nanoparticles for potential magnetic and/or optical manipulation.

An atomistic scheme is developed based on constructed n-body potential to investigate the glass-forming composition region and atomic configurations in Ni–Zr–Ti system. The glass-forming ranges derived from the n-body potentials through molecular dynamics simulations for the binary Ni–Zr, Ni–Ti, Zr–Ti, and ternary Ni–Zr–Ti systems turns out to be very compatible with theoretical studies and experimental observations. Moreover, the coordination numbers (CNs), microchemical inhomogeneity parameter, and Honeycutt and Anderson pair analysis are also computed to exam the local atomic configurations during crystal-to-amorphous phase transition. It is found that average total CNs of amorphous phases are significantly larger compared with those in solid solution counterparts, owing to the increased fractions of CNs from 13 to 16. A tendency in forming the chemical short-range orders also exists in binary and ternary metallic glasses in the Ni–Zr–Ti system and icosahedra-related atomic configurations play important role in forming those orders.

Amorphous ribbons of (Fe1-xCox)88Zr7B4Cu1 (x = 0.2, 0.35, 0.5, and 0.6) alloys were annealed to produce a nanocrystalline phase dispersed in the amorphous matrix. Precision lattice parameter calculation showed that composition of the nanocrystalline phase is Fe73Co27 for all the alloys irrespective of initial alloy composition. This result was well corroborated with the Mössbauer results. Saturation magnetization of annealed ribbons was almost same for all the alloys, however, coercivity increases with Co content.

A family of ultrahigh strength Co-based bulk metallic glasses (BMGs) with critical diameters up to 2 mm is synthesized in Co65–xTaxB35 (at.%, x = 5–10) alloys by copper mold casting. The improved glass-forming ability associated with near eutectic compositions is attributed to the appropriate addition of Ta. The glassy alloys exhibit high glass transition temperature of 930–975 K, ultrahigh compressive strength of 5.6–6.0 GPa, high specific strength of 639–654 N·m/g, Vickers hardness of 15–16 GPa, and distinct plastic strain of 0.5–1.5%. The strength and the specific strength are the highest values reported for bulk metallic materials known so far. Several universal criteria correlated with the thermal properties, elastic constants, and mechanical properties were validated in the Co-based BMG system. These Co–Ta–B BMGs combining with superior mechanical properties, high thermal stability, and simple elemental composition are significant for scientific research as modeling materials and industrial application as advanced structural materials.

Improved room temperature plasticity was achieved by microalloying Cu in a series of (Fe71Nb6B23)100−xCux (x = 0, 0.25, 0.5, 0.75, and 1) glass matrix alloys with tunable size and volume fraction of precipitates composed of α-Fe and Fe23B6 phases. When ∼10-nm-sized nano-scale precipitates are formed with a size comparable to the shear bandwidth by controlling the added content of Cu, the (Fe71Nb6B23)99.5Cu0.5 alloy exhibits a maximum plastic strain of 4.3 ± 0.8% with pronounced multiple shear banding. A further increase in the size of the precipitates up to micrometer scale results in catastrophic fracture accompanied with irregular cracks, revealing that the fracture mechanism of the different alloys is controlled by the precipitate size.

In this work, two- and three-parameter Weibull statistics were used for analyzing the variability of fracture strength for Zr55Ti2Co28Al15 bulk metallic glass (BMG), both in compression and in tension testing. In contrast to the compression in which the specimens fail via the massive shear-off, however, failure mode in tension for the as-cast BMG is flaw-controlled crack opening (mode I or mixed mode) due to the presence of cast defects such as porosity. As a result, dispersion of compressive fracture strength is rather uniform. For the BMG rods of 6 mm in diameter, the three-parameter Weibull modulus m3p and threshold stress σμ (below which no failure occurs) are 3.4 and 1780 MPa, respectively. However, tensile fracture strength of the BMGs manifests a large variability, in a range of 310–1690 MPa. In terms of fracture surface morphology, the specimen failure at different stress is associated with two types of defects: large pores on/near the surface of specimens and small internal pores. Using bimodal and three-parameter Weibull analysis, the Weibull modulus m1 and threshold σμ1 at lower strength level are 1.8 and 250 MPa, respectively, suggesting a modest reliability. One should exercise caution, therefore, in interpreting the reliability of as-cast BMG materials only simply in terms of the compression tests, small-sized samples, and tow-parameter Weibull analysis. Like the conventional metal castings, controlling the processing conditions to minimize the cast defects is critical issue to ensure the reliability of BMG materials.

The microstructures of Zr70Cu30 and Zr70Ni30 metallic glasses (MGs) were investigated via the synchrotron radiation techniques combined with the reverse Monte-Carlo simulations. Although Cu and Ni are neighbor elements in the periodic table and their atomic radii are almost the same in length, it is found that atomic- and cluster-scale structural differences occur between these two Zr-based MGs. In particular, the relatively regular clusters caused by the narrow distributions of atomic separations and bond angles are detected in Zr70Cu30. This is the structural origin of the different glass-forming abilities in ZrCu and ZrNi alloys. This work has implications for understanding of the glass-forming mechanism in this class of glassy materials.

The failure mechanism of lead-free solder interconnections of chip scale package–sized Ball Grid Array (BGA) component boards under thermal cycling was studied by employing cross-polarized light microscopy, scanning electronic microscopy, electron backscatter diffraction, and nanoindentation. It was determined that the critical solder interconnections were located underneath the chip corners, instead of the corner most interconnections of the package, and the highest strains and stresses were concentrated at the outer neck regions on the component side of the interconnections. Observations of the failure modes were in good agreement with the finite element results. The failure of the interconnections was associated with changes of microstructures by recrystallization in the strain concentration regions of the solder interconnections. Coarsening of intermetallic particles and the disappearance of the boundaries between the primary Sn cells were observed in both cases. The nanoindentation results showed lower hardness of the recrystallized grains compared with the non-recrystallized regions of the same interconnection. The results show that failure modes are dependent on the localized microstructural changes in the strain concentration regions of the interconnections and the crack paths follow the networks of grain boundaries produced by recrystallization.

Porous zirconium metal microspheres were synthesized successfully by a combustion technique using ZrO2 + 2Mg starting mixture. In this process, a controlled amount of KClO3 + 3Mg is mixed with ZrO2 + 2Mg to enable a self-sustaining combustion process and to promote a reduction of the ZrO2. The framework structure, morphology, and porosity of zirconium microspheres were determined using various techniques. Microscopic visualization suggested that the spherical structure has macroporous windows of diameter ∼0.5–5.0 μm and the space between the macropores has a wormhole-like mesoporous/microporous structure. The mesoporous structure had a pore diameter of ∼1.19 nm. This procedure provides an easy method for the synthesis of porous microspherical assemblies of Zr composed of submicrometer size particles.