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Since 2020, synchrotron radiation facilities in several Asia-Pacific countries have been collaborating in a major project called "SYNAPSE"(Synchrotrons for Neuroscience: an Asia-Pacific Scientific Enterprise). They use x-ray imaging to attack in a coordinated fashion one of the major issues in modern science: the structure of animal and human brains, including neurons and connections. The objective is to develop Google-like maps also including detailed structural and functional information for selected regions of interest. The sheer mass of data needed for the objective poses huge problems for the acquisition, processing, storage and use of images. In order to complete the task within a reasonable time, the key element of the SYNAPSE strategy is the parallel and coordinated work of several facilities on the same specimens. This article reviews different aspects of the enterprise, including the foundations of synchrotron radiation, coherence and of its role in advanced imaging, electron accelerators, x-ray optics and detectors. This will provide the foundation for an extensive presentation of the different components of SYNAPSE, with an overview of results already obtained within the consortium.

Mapping the large neural networks of animal and human brains is a fundamental but so far elusive task, because of the massive amount of data and the consequent prohibitively long image taking and processing times. We developed an effective strategy called “AXON” (Accelerated X-ray Observation of Neurons) to solve this problem. AXON can achieve comprehensive whole-brain mapping within a reasonable time by combining fast image taking and processing, plus two other critical performances: three-dimensional (3D) imaging with high and isotropic spatial resolution, and multi-scale resolution. We successfully tested this strategy with coordinated experiments at four synchrotron facilities in Japan, Taiwan, Singapore and Korea on two animal models, Drosophila and mouse. Its performances notably allowed full 3D mapping of the Drosophila brain in a few days. With reasonable improvements, AXON can deliver full mapping of large animal and human brains on a realistic time scale of a few years.

Highly stretchable polymer composite microtubes of poly(methyl methacrylate)/polypyrrole (PMMA/PPy) were produced as a microarch shape by a meniscus-guided approach using colloidal solutions of the composite polymers. The polymer composite (PMMA/PPy) microarches show high stretchability up to 80% maintaining the electrical properties. Moreover, the microarches endure repeated stretching over 10 4 ( 9 × 10 2 ) cycles at 20% (80%) stretching without degradation of the electrical properties. The stretchable PMMA/PPy microtube arches are demonstrated as gas sensors with persistent sensitivities and response (recovery) times up to 80% stretching for various NH 3 concentrations. These robust properties of the stretchable PMMA/PPy microtube arch sensors can be suitable for portable sensing devices operating under extreme stretching conductions to be used in research laboratories and chemical processing industries for chemical leak detection and environmental monitoring.

The optical glow of ceramics that becomes established during the constant state of flash, known as Stage III in flash sintering experiments, is investigated. The specimen temperature in this state is obtained from in situ experiments at the Pohang Light Source II. The measurements of the specimen temperature agree very well with the predictions from the black body radiation model. The optical emission spectrum from the specimen is measured from the visible into the deep infrared, and compared with black body radiation that would have been expected from Joule heating. It is concluded that the specimens radiate by electroluminescence, which is ascribed to electron–hole recombination of excitons. The phenomenon is likely the same as discovered by Nernst at the turn of the twentieth century.

Colloids (colloidal particles or nanoparticles) and their in-situ characterizations are important topics in colloid and interface science. In-situ visualization of colloids with X-ray microscopy is a growing frontier. Here, after a brief introduction on the method, we focus on its application for identifying nanoscale wettability of colloidal particles at fluid interfaces, which is a critical factor in colloidal self-assembly. We discuss a quantitative study on colloidal wettability with two microscopic methods: (i) X-ray microscopy by visualizing natural oil–water interfaces and (ii) confocal microscopy by visualizing fluorescently-labeled interfaces. Both methods show consistent estimation results in colloid–fluid interfacial tensions. This comparison strongly suggests a feasibility of X-ray microscopy as a promising in-situ protocol in colloid research, without fluorescent staining. Finally, we address a prospect of X-ray imaging for colloid and interface science.

Heteroepitaxial ZnO films were grown by pulsed laser deposition on various substrates such as GaN-buffered C-Al 2 O 3 , C-Al 2 O 3 , A-Al 2 O 3 , and R-Al 2 O 3 . The epitaxy nature of the films was investigated mainly by synchrotron X-ray diffraction. The results showed that the GaN interlayer plays a positive role in growing an unstrained, well-aligned epitaxial ZnO film on the basal plane of Al 2 O 3 . Importantly, the ZnO film grown on R-Al 2 O 3 has two differently aligned domains. The dominant (1 1 0) oriented domain has much better alignment in the in-plane direction than the minor portion of (0 0 1) oriented domain, while in the out-of-plane direction the two domains have almost the same mosaic distribution.

Crack-free interfaces can be achieved in wafer-bonded Ge/Si by using patterned grooves. Using synchrotron radiation phase-contrast imaging and scanning electron microscopy, we observe cracking that is induced by thermal stresses in thin (hGe ⩽ 0.5hSi) Ge wafers on smooth Si substrates. Theoretical calculation shows a remarkable reduction in thermal stresses in Ge wafer bonded to grooved Si substrate. We demonstrate the fabrication of crack-free Ge/Si (hGe = 0.5hSi) structure by patterned grooves, as confirmed by an ohmic I–V characteristic across the heterojunction.

Au/TiO2 nanocomposite particles were synthesized by a method based on intense X-ray irradiation without adding any reducing agent or stabilizer. The nanocomposite exhibits promising photocatalytic and biological properties at physiologically relevant concentration ([Au] = 0.028 mM, [TiO2] = 0.5 mM). The structure and photocatalysis were examined by X-ray diffraction, electron microscopy and ultraviolet-visible spectroscopy demonstrating that gold nanoparticles of 2-5 nm size were successfully deposited on TiO2 nanoparticle surfaces. The nanocomposite exhibited good colloidal stability within a typical cellular environment and was nontoxic to cancer cell according to evaluations under controlled conditions. The Au/TiO2 nanoparticles were also found to enhance the photocatalytic efficiency of UV radiation and even more that of X-ray radiation. In vitro studies indicated that the cell-killing effect under X-ray irradiation is more pronounced with the addition of Au/TiO2 nanoparticles than of bare TiO2 nanoparticles. (C) 2009 Elsevier B.V. All rights reserved.

Experiments performed using the novel technique of real-time microradiography with coherent X-rays provided clear experimental evidence of the “fibrilization” phenomenon of electrical conductive microspheres between a copper microelectrode (anode) and platinum plate (cathode) in electrorheological fluids under an applied voltage (about 2 kV/mm). The surface-conductive polymeric microspheres were prepared by the adsorption of multi-walled carbon nanotubes (MWCNTs) on the surface of poly(methylmethacrylate) microspheres (6.5 μm). We also observed the process of MWCNT adsorption on the polymeric microspheres in the MWCNT dispersion containing surfactants and the assembly of MWCNTs-coated microspheres during their sedimentation in real-time by microradiography.

Reductant, stabilizer-free colloidal gold solutions were fabricated by a new room-temperature synchrotron X-ray irradiation method. The influence of process parameters such as the pH value and the exposure time on the structure of gold nanoparticles was investigated. The mechanisms underlying the X-ray-triggered reduction of gold ions and the formation of gold clusters are discussed in detail. The X-ray irradiation derived highly concentrated gold nanoparticles are readily to be re-dispersed and possess suitable colloidal stability within cellular environment. The characterization included a study of the possible cytotoxicity for the EMT-6 tumor cell line: the negative results indicate that the gold clusters produced with our approach are biocompatible.

Adverse health effects are associated with the inhalation of a variety of atmospheric particles. To study the lung injuries caused by aerosol PM2.5, synchrotron radiation (SR) X-ray phase-contrast imaging technique was used. Nude mice were inoculated with PM2.5 samples collected from suburban area (JD), industrial area (BS) and traffic tunnel (DPQ) of Shanghai. From X-ray phase-contrast images of lung tissues, apart from blood vessels and structures of alveoli, even hemorrhage spots of several microns caused by the inflammation were clearly observed. The studies showed that the PM2.5 samples collected from the traffic tunnel (DPQ) produced higher level of lung injury, followed by the aerosol samples collected from industrial area (BS) and suburban area (JD). Our studies also helped us to understand the process of lung injuries caused by aerosol particles. (c) 2007 Elsevier B.V. All rights reserved.

We developed a novel approach to prepare Ni–Au composite nanoparticles using synchrotron radiation X-rays. Ni–Au particles dispersed in aqueous solutions were synthesized with two different irradiation strategies. The first is by exposing to X-rays a mixed electroless solution of Ni and Au at two different temperatures, trying to nucleate Ni nanoparticles homogeneously at room temperature and to deposit Au subsequently on them at the high temperature of 70 °C. The second strategy is to change the pH value of the mixed solution, directly leading to the formation of Ni–Au nanoparticles. In both cases, the Ni–Au composite nanoparticles were successfully formed, as confirmed by the observed ferromagnetic behavior and by the evolution of the Au surface plasmon resonance band.

We reported a simple approach to generate gold colloidals from HAuCl 4 containing aqueous solution by synchrotron X-ray irradiation at room temperature. Gold colloidals were readily formed with reasonable yield. It was also observed that the addition of NaHCO 3 tremendously modified the size and size distribution of gold nanoparticles. Our preliminary drug carrying experiment showed that thus produced gold nanopartricles could successfully carry anti-tumor drug and possess potential for drug delivery applications.

We introduce a new X-ray diffraction microscopy technique capable of coupling grain orientation with its spatial location in textured thin-films. The principle is based on the combination of X-ray topography with diffractometry. High-resolution X-ray diffractometry using a scintillation detector is utilized to measure orientational distribution of individual grains. Then X-ray topography using CCD system is applied to determine the spatial locations of the angularly resolved grains. The successful application is demonstrated for grain-on-grain epitaxial alignment between the film and the substrate in Y 2 O 3 /Ni. The feasibility and the limitations of the technique are discussed.

Using a scintillator-CCD imaging system, we successfully conducted a synchrotron white beam Laue topography (WBLT) experiment. It is demonstrated that this approach is able to provide a high-resolution microtopograph of p/p + Si (1 0 0). Optimum condition for high-resolution imaging is obtainable from the incident angle dependence of geometrical resolution. Black and white dislocation contrast suggests the potential of WBLT in characterizing dislocation structure.

In this study, the degradation behavior of oxide cathodes for cathode ray tubes (CRTs) is described using the stretched exponential model, which has been successfully used to describe the dynamics of complex systems characterized by heterogeneity. We derive a longevity equation from the two parameters: (i) characteristic life and (ii) heterogeneity parameter, which characterize the stretched exponential model. From the temperature dependences of the two parameters in the longevity equation, we reveal that the longevity follows the Arrhenius relation in oxide cathodes. The longevity equation and the Arrhenius relation enable us to predict the longevity in early life. The stretched exponential degradation is explained based on the heterogeneity of oxide cathodes.

Early stage growth behavior of vertically aligned ZnO nanoneedles by metalorganic chemical vapor deposition was investigated mainly using X-ray diffraction. In very early stages of growth, 3-dimensional island-like ZnO grains initially nucleate and grow on the substrate surface, then cover its whole surface, consequently resulting in formation of a continuous layer. The layer grows epitaxially with a 30° rotation of ZnO basal planes with respect to the Al 2 O 3 (0 0 0 1) substrate, while being coherently strained to the substrate. On top of the existing well-aligned continuous ZnO layer, vertically as well as laterally aligned nanoneedles start to grow as the growth proceeds further. The onset of the nucleation and growth of nanoneedles is likely to be associated with the relaxation of a compressive strain developed in the continuous ZnO layer formed before the growth of nanoneedles.

The growth behavior of ultrathin (∼5 nm) SrRuO3 films prepared by pulsed laser deposition (PLD) on SrTiO3 (001) was investigated particularly as a function of growth temperature mainly using synchrotron X-ray diffraction. At a critical growth temperature (~500 °C), below which no crystallization occurs, an epitaxial SrRuO3 film starts to grow with a broad distribution of single (110) domain along the film growth direction maintaining the epitaxial relationship of SrRuO3[001]/SrTiO3[100] and SrRuO3[−110] SrTiO3[010]. Its in-plane and out-of-plane crystal alignments improve sharply when a higher growth temperature of 600 °C is applied, presumably due to the more thermal energy supplied to the substrate. However, more increase of the growth temperature to 650 °C results in no enhancement of atomic ordering but a rougher surface, suggesting that a careful adjustment in the growth temperature is needed to grow an epitaxially well aligned SrRuO3 film possessing a smooth surface.

We investigated the microstructural evolution of ZnO/Al 2 O 3 (0 0 0 1) films with and without an ultra-thin (4 nm) ZnO buffer that was grown at a low temperature (LT) of 300 °C using real time synchrotron X-ray scattering, atomic force microscopy, and high resolution electron microscopy. It is shown that the ultra-thin two-dimensional (2D) layers play a critical role for improving the ZnO layer quality, by inducing 2D growth mode instead of 3D mode at 500 °C in early stage. The ZnO films grown on the ultra-thin buffer exhibited structural coherence between the surface and the interface in the substrate normal direction in early stage. The great enhancement of the structural quality was attributed to the strain accommodation by the 2D ultra-thin buffer.

We investigated the effect of evaporation on the surface morphology of c-oriented epitaxial ZnO (40 nm thick)/Al2O3(0 0 0 1) films during postdeposition annealing using real time synchrotron X-ray scattering and atomic force microscopy (AFM). We find that evaporation as well as grain coalescence play crucial roles on the surface morphology of the ZnO/Al2O3(0 0 0 1) films. Grain growth occurring in initial stage of annealing forms facets with higher surface energies than the (0 0 0 1) planes. By the preferential evaporation of the prism planes, the surface morphology of the ZnO film eventually evolves into 2D flat (0 0 0 1) surface at 800 °C, as confirmed by AFM. The real time measurement of the film thickness during annealing also supports the effect of the evaporation on the morphology. The evaporation rate is high in initial stage by the preferential evaporation from high energy facets but slows down after transition to the flat (0 0 0 1) surface.

Europium doped yttrium oxide (Y 2 O 3 :Eu) luminescent thin films were grown on Si(0 0 1) substrates using a pulsed laser deposition technique and their microstructures and growth behavior were investigated by synchrotron X-ray scattering and atomic force microscopy. We observed that the surface morphology of the Y 2 O 3 :Eu films was very smooth with typically a 0.5-nm root mean square roughness for the films up to 750 nm in thickness and the film strain increased gradually with film thickness, suggesting that the Y 2 O 3 :Eu films are grown with a layer-like growth mode. Grown with the (1 1 1) preferred orientation, the Y 2 O 3 :Eu films significantly improved in crystallinity with film thickness, showing a characteristic red luminescence of Y 2 O 3 :Eu materials.

We used phase contrast radiography to study the electro-deposition of Zn in real time and with high lateral resolution. Using unmonochromatic synchrotron X-rays and an optics-less imaging setup, we were able to obtain real-time radiographs of the electro-deposition in situ with gm resolution. A detailed analysis of the microstructure evolution relates the different growth parameters - such as the electric current density, the voltage bias, the pH value and the ion concentration - to very different growth morphology, ranging from film, porous, whisker and dendrite deposition. This link is both global and local. Local variations of the metal ion concentration in the electrolyte were also successfully imaged and the density profile is used to compare with the standard theory to explain the phenomenon of metal ion depletion near the electrode. The potential application of this technique to study growth with micropatterned electrodes and pulsed electric current is evaluated. (C) 2002 Elsevier Science B.V. All rights reserved.

We first present real-time microradiology of disintegration of self-fluxing iron ore sinters in low temperature reduction using highly collimated synchrotron source. The experiments were performed on the 5C1 beamline at PLS (Pohang Light Source, Pohang, Korea), operating at 2.5 GeV. We used unmonochromatized (“white”) light with no optical elements except beryllium windows. The images of the crack superimpose, on the two-dimensional projection of a three-dimensional phenomenon, suggest that cracks are always initiated from pores in the sinters and propagate along neighboring pores. Interestingly, cracking occurs mostly on macropores (>800 μm), preferentially initiated from stress concentrated sites on pore surfaces. This dynamic study of the disintegration of sinters clearly shows that the crack initiation temperature is as low as 450 °C.

By irradiating a solution in electroless Ni deposition using synchrotron X-rays, Ni composite was found to nucleate homogeneously and eventually precipitate in the form of nanoparticles. The size of the nanoparticles precipitated is rather uniform (100–300 nm depending on the applied temperature). By the addition of an organic acid, well-dispersed nanoparticles could be effectively deposited on glass substrate. The hydrated electrons (eaq−), products of radiolysis of water molecules by synchrotron X-rays, may be responsible for the effective reduction of the metal ions, resulting in homogeneous nucleation and nanoparticle formation. Our results suggest that synchrotron X-ray can be used to induce solution precipitation of nanoparticles and therefore lead to a new method of producing nanostructured particles and coating.

Phase contrast radiology using unmonochromatic synchrotron X-ray successfully imaged the grain boundaries of Al and AlZn alloy without contrast agent. Combining the high penetration of X-ray and the possibility of 3D reconstruction by tomorgraphy or stereography method, this approach can be very used for nondestructive characterization of polycrystalline materials. By examine the images with 3D perspective, we were able locate the observed void-like defects which lies exclusively on the grain boundary and identify their origin from last stage of the rolling process. We studied the Ga Liquid metal diffusion in the AlZn alloy, under different temperature and stress conditions. High resolution images, ∼2 μm, of Ga liquid metal diffusion in AlZn were obtained in real time and diffusion paths alone grain boundaries and surfaces were clearly identified. Embrittled AlZn responses to the tensile stress and fractures in a drastic different manner than the pure AlZn. These results, although very much expected from the known weakening effect of the liquid metal embrittlement demonstrated, however, that this particular radiology method is fully capable of dynamic study in the micrometer scale.

The CoCrPt/Ti/NiP films for perpendicular magnetic recording were studied using X-ray scattering and anomalous X-ray scattering. When the NiP seed layer was used, the long range order of the texture peak of the magnetic film decreased and less Co was associated with this Bragg order. The structural results were consistent with the observed increased coercivity and decreased magnetization due to the increased magnetic grain isolation caused by the presence of NiP seed layer.

We investigated the structure and alignment of epitaxial Y2O3 and Gd2O3 films on cube textured Ni(0 0 1) substrates and used the findings to develop a general interpretation of the morphology of RE2O3 films (RE=Y or a rare earth element) on cube textured nickel and nickel-based alloys. The [1 0 0] axis of RE2O3 oxides mostly prefers aligning to the Ni[1 1 0] axis, while the [0 0 1] axis is aligned with the Ni[0 0 1] axis. This (2 2 ×2 2 )R45° extended domain matching (EDM) seems to be favored by a high coincidence site density (CSD) with the Ni(0 0 1) surface atoms, in spite of the existence of large lattice mismatches to Ni(0 0 1). Meanwhile a 3×3 EDM is not favored on Ni(0 0 1), in spite of the relatively small lattice mismatch to Ni(0 0 1), because of the existence of a low CSD. The broad mosaic distributions of RE2O3(0 0 l) grains (6–9° full-width at half-maximum) indicate that RE2O3 layers prefer growing along the Ni(0 0 1) planes rather than along the Ni surface, a condition presumably induced by the favorable energetics for EDM.

We have studied the influence of metal elements on the passivation of stainless steel (SS) 430 (18Cr) and 444 (18Cr–2Mo) by real time X-ray absorption near edge spectroscopy. We developed an electro-chemical cell that is suitable for in situ electro-chemistry experiments. The behavior of Fe, Cr and Mo elements of SS 430 and 444 was studied in passive region reaction in a borate buffer solution (pH 7.0). We found that the Cr 2 O 3 /Fe 2 O 3 ratio gradually decreased with passivation time due to the oxidation of Cr 2 O 3 to CrO 4 2− , indicating weakening of passivity. In the meanwhile, the amount of Mo at passive films increased with passivation time. The improvement of passivity in the SS 444 is mainly attributed to the substitution of Cr oxide by Mo oxide in the passive film.

We studied the microstructure of a Pd overlayer deposited on a cube textured Ni(0 0 1) substrate using synchrotron X-ray scattering. We find the existence of an epitaxial Pd–Ni interlayer between the epitaxial Pd layer and the Ni substrate. The Pd–Ni interlayer, which is compressively strained in a manner similar to the Pd overlayer, seemingly acts to relieve the strain at the Pd/Ni interface caused by the Pd–Ni lattice mismatch. The Ni mosaic distribution of our samples is multiply spiked with a rocking angle spread of ∼16°, which reconciles the previously reported observation of saw tooth peaks on top of a Gaussian distribution for a similarly prepared Pd on Ni specimen. The observed sharpening of the mosaic distributions for the Pd(0 0 2) grains (full-width at half-maximum (FWHM)=1.95°) and for the (0 0 2) grains of Pd–Ni interlayer (FWHM=3.0°) indicates that the Pd and Pd–Ni(0 0 2) layers conform to the surface morphology instead of to the (0 0 1) crystallographic planes of Ni-substrate grains.

In situ crystallization of α-Fe 2 O 3 /α-Al 2 O 3 (0 0 0 1) thin films was studied in real-time synchrotron X-ray scattering experiments. We find the coexistence of α-Fe 2 O 3 (hexagonal) and Fe 3 O 4 (cubic) interfacial crystallites (∼50-A-thick), well aligned [0.02° full-width at half-maximum (FWHM)] to the α-Al 2 O 3 [0 0 0 1] direction, in the sputter-grown amorphous films. As the annealing temperature increases up to 750°C, the cubic stacking of the Fe 3 O 4 crystallites gradually changes to the hexagonal α-Fe 2 O 3 stacking, together with the growth of the well-aligned (WA) (0.02° FWHM) grains from the α-Fe 2 O 3 crystallites. In the meanwhile, heterogeneous nucleation starts to occur on the substrate at ∼600°C, resulting in the formation of misaligned (1.39° FWHM) α-Fe 2 O 3 grains. Our study reveals that the interfacial crystallites act as a template for the growth of the WA α-Fe 2 O 3 grains.

Low temperature nucleation of GaN on (0001) sapphire is investigated. Depositions were made for 20–180 s at 560 °C by metalorganic chemical vapour deposition (MOCVD). It is shown that the shortest deposition times give rise to the formation of crystallites with the sphalerite structure. Subsequently, the density and the size of nucleation islands increase and they start to transform to wurtzite from the interface with the substrate. From the start, the nuclei contain misfit dislocations. Calculations of residual relaxations done on GaN islands for the 60 and the 120 s nucleation layers, respectively, show that the 120 s nucleation is probably more relaxed.

The initial stages of low temperature GaN buffer layers grown on (0001) sapphire by metalorganic chemical vapour deposition are investigated using conventional and high resolution electron microscopy (HREM). Different deposition times are used in order to observe the evolution of the buffer layer microstructure. Three-dimensional nuclei with the (0001)GaN//(0001)sapphire and [0 1 10]GaN//[11 2 0]sapphire alignment are formed, increasing in height and width with the growth time. Consequently, coalescence is taking place, and the structure of islands is modified. Hexagonal stacking is developing through these islands, but the cubic structure is predominant. A high density of stacking faults and microtwins formed. It is found that GaN islands contain misfit dislocations at the interface with the sapphire substrate. Calculations of residual strain show a transition from a compressive to a tensile strain when the coalescence of islands is operating.

Conductive LaNiO 3 (LNO) thin films were prepared on Si(001) by pulsed laser deposition and their microstructures were investigated using synchrotron X-ray scattering and atomic force microscopy. We observed that the surface morphology of the LNO thin films was extremely smooth with typically a 1.0-nm root-mean-squared roughness for films up to 360 nm in thickness and the film strain increased monotonically with the film thickness, suggesting that the LNO/Si(001) films be grown with a layer-like growth mode. Grown with the (00 l ) preferred orientation, the LNO films showed a significant anisotropic structural order; the coherence length of the out-of-plane stacking order was one order of magnitude larger than that of the in-plane atomic order.

Highly collimated synchrotron sources are the essential ingredient of novel radiology and micro-radiology techniques for materials science. medicine and biology-with contrast based on the refractive index rather than on absorption. We were able to implement a real-time version of such techniques. Successful test studies included thin-foil breaking and electrodeposition processes in the areas concerning materials properties. Meanwhile. extensive effort was dedicated to obtain high-quality X-ray images of live specimens on a microscopic scale and in real time. These tests achieved a lateral resolution better than 2 mum and a time per image of 10 ms, with clear potential for further improvements. The images revealed in great detail moving parts of different specimens. opening the way to a wide variety of applications in the life sciences, medicine and materials science. (C) 2001 Published by Elsevier Science B.V.

We present several successful test cases of using photoelectron emission microscopy (PEEM) for photon energy up to 25 keV. First, the full extended X-ray absorption fine structure analysis was implemented in areas as small as 100 mum(2) for transition-metal K edge absorption spectra and, therefore, demonstrated the feasibility of combining structural and chemical analysis with hard-X-ray absorption spectroscopy with high lateral resolution. We also show that PEEM can be used in a transmission (radiography) mode as an imaging detector for hard-X-ray, This approach again leads to the unprecedented 0.3 mum lateral resolution, particularly critical for the use of coherence-based phase contrast techniques in real time X-ray radiology. (C) 2001 Elsevier Science B.V. All rights reserved.

We demonstrate with practical tests that a photoelectron emission microscope (PEEM) can be advantageously used as a high-lateral-resolution detector of X-rays. The advantages of this approach are discussed, in particular for coherence-based techniques. (C) 1999 Published by Elsevier Science B.V. All rights reserved.

In this study, we investigated the effect of a shield on the phase formation of the BiSrCaCuO film deposited by in-situ, off-axis sputtering. Here we set up a semicircular shield in the normal direction to the substrate for the blocking of the oxygen anions flying linearly to the growing film. The resputtering of the superconducting film by the oxygen anions could be effectively suppressed by using the shield. Moreover, we could deposit the 2223 high- T c phase at relatively low substrate temperatures from 590°C to 640°C even without the addition of Pb. As the substrate temperature was increased, the phase of the film, interestingly, was changed from the 2212 phase (or the 2212 phase plus the 2201 phase) to the 2223 phase and then to the 2212 phase again.

Oxygen is normally used as a sputtering gas with or without argon for the sputter deposition of the BiSrCaCuO superconductor. Then the grown films are frequently found to have poor qualities by severe resputtering. The purpose of this study is to identify the resputtering particle during the sputter deposition and to investigate its effect on the film growth. The experimental results support the assertion that the resputtering particle is the oxygen anion. We speculate that the oxygen anions pass through the plasma and arrive on the substrate surface nearly in a straight line. The bombardment by the oxygen caused a decrease in the crystallinity and the increase in the surface roughness of the film, and caused the a -axis orientation. A method to prevent the resputtering of the film by the oxygen anions was developed and the very smooth film of the 2212 phase with the c -axis orientation could be grown.

We reveal the existence of interfacial, epitaxial, Pd grains in an as-deposited Pd film evaporated on GaN (0001) at room temperature. The origin of the Pd epitaxy was attributed to 6/7 matched interface structure. The Pd film was completely transformed to Ga 2 Pd 5 and Ga 5 Pd gallides in epitaxial relationships with GaN at an annealing temperature of 700°C.

The microstructure in GaN nucleation layers was studied in synchrotron X-ray scattering and transmission electron microscopy experiments. We revealed the existence of tensile-strained interfacial domains, which was originated from 6/7 matched interface structure.

In order to understand the formation mechanism of the superconducting phases, amorphous BiSrCaCuO films prepared by RF magnetron sputtering were rapidly cooled after various annealing processes. The 2201 phase began to grow at 600°C and the 2212 phase with c -axis orientation was grown up to 870°C. Two kinds of needle-like secondary phases which were rich in Ca and Cu were also observed from 870°C, along with a partial melting in the matrix. After holding at 880°C and 890°C for 6 h, the matrix was mostly liquefied and transformed to the 2201 phase after rapid cooling. However, when slowly cooled at 1°C/min, the 2212 phase with the c -axis orientation was obtained. On the other hand, when slowly cooled after holding at 870°C for 6 h, the remaining 2212 phase and the co-existing liquid phase within the matrix could also produce the 2223 phase.

Reactively sputtered TiN coatings on the relatively soft substrate, Crofer 1700 (Vickers' hardness about 176 HV), were subjected to a scratch test for adhesion. The critical load of the coating/substrate combination is defined as the load at the onset of coating failure as cracking or loss of the coating that causes an increase in acoustic emission. For example, at the critical load of a thicker coating (approximately 1.5 μm), not only cracking but also loss of the coating were observed with an increase in acoustic emission. However, at the critical loads of thinner coatings (1.2 μm or less), coating loss was not observed in spite of an increase in the emission but coating cracking did occur. A failure model is suggested for the given coating plus soft substrate system. Using this model, the maximum observed in a typical acoustic emission curve is explained.