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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.

The direct optical wiring (DOW) technology which is based on the 3D writing of optically transparent polymer wires using a meniscus-guided method is employed to develop multi-mode optical interconnects for VCSEL-MMF applications. This DOW method, similar in concept to conventional electrical wire bonding, does not require any chemical reactions. DOW bonding is used to optically connect high-speed VCSELs and standard OM3 multi-mode fibers (MMFs). The resulting simplified lens-free transmitter modules show a high coupling efficiency (65%) and 12 Gbit/sec error-free transmission per-channel, which is satisfactory for optical HDMI 2.1 applications. In the presentation, the 4K-60Hz performance transmitted through the HDMI2.1 will be demonstrated and extended single-mode results introduced. We believe that DOW bonding can be a powerful platform technology for optical interconnect and photonic integration for innovative industrial and academic photonic applications.

Bulk AlN crystals grown by sublimation on SiC substrates exhibit relatively high dislocation densities. The kind of defect formation at early growth stages influences the structural quality of the grown crystals. In this work, the dislocation distribution near to the interface is understood through investigation of thin (≤1.5 mm) continuous (non-cracked) freestanding crystals obtained in one process with the evaporation of the substrates. The AlN specimens were characterized using synchrotron radiation imaging techniques. We revealed by triple-axis X-ray diffraction study that, near to the former interface, randomly distributed dislocations configured to form boundaries between $$\sim $$ 0.02 $$^{\circ }$$ misoriented sub-grains (from [0001] direction). Threading dislocation structure similar to that in epitaxial GaN films was not detected. To explain these observations, a theoretical model of misfit stress relaxation near the interface is suggested.

The morphology of a macrodefect in a single-crystal silicon carbide wafer has been investigated by the computer simulation of an experimental X-ray phase-contrast image. A micropipe, i.e., a long cavity with a small (elliptical in the general case) cross section, in a single crystal has been considered as a macrodefect. A far-field image of micropipe has been measured with the aid of synchrotron radiation without a monochromator. The parameters of micropipe elliptical cross section are determined based on one projection in two directions: parallel and perpendicular to the X-ray beam propagation direction, when scanning along the pipe axis. The results demonstrate the efficiency of the phase contrast method supplemented with computer simulation for studying such macrodefects when the defect position in the sample volume is unknown beforehand.

The characteristics of synchrotron X-ray sources--quite different from those of conventional sources--are exploited by several new imaging techniques. These techniques expand the capabilities of conventional radiology and find interesting application in special cases. We briefly review the basic principle, applications and limitations of the most important of them: monochromatic mammography, two-wavelength digital subtraction angiography, phase-contrast/edge-enhancement imaging, diffraction-enhanced imaging and microtomography.

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.

It has been generally accepted that any reaction between micropipes in silicon carbide (SiC) crystals requires a direct contact of the micropipes. We propose a new model of contact-free reactions that are realized through the emission and absorption of full-core dislocations by micropipes. This model can explain the correlated reduction in micropipe radii in the samples with low micropipe densities which has been observed in synchrotron radiation (SR) phase contrast images supported by computer simulations. We provide a theoretical description of a contact-free reaction between two parallel micropipes.

Sliced SiC boule grown by physical vapor transport is investigated using synchrotron white beam phase contrast imaging combined with Bragg diffraction. The evolution of defects is revealed. In the early growth stage, foreign polytype inclusions not only induce massive generation of full-core dislocations and dislocated micropipes but also attract them, forming slit-type pores at the boundaries of inclusions. In the intermediate stage, when inclusions stop to grow and become overgrown by the matrix, the pore density significantly reduces, which is attributed to their transformation into new micropipes. In the later stage, the micropipe density decreases, providing evidence for their partial annihilation and healing. Mechanisms for the evolution from inclusions to pores and finally to micropipes during the crystal growth are further discussed.

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.

Colloidal Ag nanoparticles were formed by X-ray irradiation in the presence of a polymer. This new synthesis method is simple, rapid and leads to a high production yield. Compared to the citrate-reduced Ag colloidal, polymer-protected Ag nanoparticles are smaller in size and more stable—and therefore suitable for biomedical application—as verified by TEM observation, XAFS measurement and optical characterization. Ag nanoparticles so produced were also visualized in solution and in real time by a visible light microscope based on dark field light scattering. The color-derived size and distribution of Ag nanoparticles correlates well with the hydrodynamic size data.

The elliptical micropipes in SiC are studied using computer simulation of the phase contrast images. The experimental measurements of "white beam" images are performed at third-generation synchrotron radiation source in Pohang, Korea. We reveal that the transmitted X-ray spectrum of a high brilliance with a pronounced maximum at 16 keV enables to form partially coherent images even for transparent objects. The computer simulation allows one to automatically determine the diameters of elliptical cross-sections based on best matches between calculated and experimental intensity profiles. We show that the micropipes studied here have extended elliptical cross-sections, sometimes rotating around the micropipe axis.

Purpose The purpose of this study is to evaluate the feasibility of phase contrast X-ray microtomography and microradiography, using a polychromatic synchrotron X-ray, for analysis of the mouse lung microstructure. Materials and Methods Normal mice were used for experiments. Some of the mouse lungs were prepared by the lung fixation-inflation method. The resulting sponge-like inflated lung samples were used for microtomography. The remaining mouse lungs were cut into 10 um sections and were used for microradiography and optical microscopic correlation. The experiments on mouse lung samples were performed at the 7B2 beamline of the Pohang Light Source in Korea. Results Phase contrast X-ray microtomography of inflated lung samples showed individual alveolar structure on 3-D reconstruction. Phase contrast microradiographs of thin lung samples showed microstructure of lung, such as alveoli and bronchioles, and were well correlated with optical microscopic images. Conclusions The results indicate that the phase contrast X-ray microtomography and microradiography using polychromatic synchrotron X-ray is feasible for evaluation of microstructure of the lung.

The advanced characteristics of synchrotron light has led in recent years to the development of a series of new experimental techniques to investigate chemical and physical properties on a microscopic scale. Although originally developed for materials science and biomedical research, such techniques find increasing applications in other domains – and could be quite useful for the study and conservation of cultural heritage. Specifically, they can nondestructively provide detailed chemical composition information that can be useful for the identification of specimens, for the discovery of historical links based on the sources of chemical raw materials and on chemical processes, for the analysis of damage, their causes and remedies and for many other issues. Likewise, morphological and structural information on a microscopic scale is useful for the identification, study and preservation of many different cultural and historical specimens. We concentrate here on two classes of techniques: in the first case, photoemission spectromicroscopy. This is the result of the advanced evolution of photoemission techniques like ESCA (Electron Microscopy for Chemical Analysis). By combining high lateral resolution to spectroscopy, photoemission spectromicroscopy can deliver fine chemical information on a microscopic scale in a nondestructive fashion. The second class of techniques exploits the high lateral coherence of modern synchrotron sources, a byproduct of the quest for high brightness or brilliance. We will see that such techniques now push radiology into the submicron scale and the submillisecond time domain. Furthermore, they can be implemented in a tomographic mode, increasing the information and becoming potentially quite useful for the analysis of cultural heritage specimens.

The fabrication of gold Fresnel zone plates, by a combination of e-beam lithography and electrodeposition, with a 30 nm outermost zone width and a 450 nm-thick structure is described. The e-beam lithography process was implemented with a careful evaluation of applied dosage, tests of different bake-out temperatures and durations for the photoresist, and the use of a developer without methylisobutylketone. Electrodeposition with a pulsed current mode and with a specially designed apparatus produced the desired high-aspect-ratio nanostructures. The fabricated zone plates were examined by electron microscopy and their performances were assessed using a transmission X-ray microscope. The results specifically demonstrated an image resolution of 40 nm.

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.

The formation of colloidal unmodified (naked) gold nanoparticles is investigated by irradiation of a precursor solution with X-rays from a synchrotron source. An interesting morphological evolution as a function of exposure time, from cross-linked network-like structure to individual particles, has been discovered. The particle size decreased with the exposure time and was influenced by the ionic strength of the precursor solution. Contrary to gamma-ray exposure, an OH radical scavenger was not required for cluster formation.

The crystallization of α-Fe2O3/α-Al2O3(0001) thin films has been studied using real-time synchrotron x-ray scattering and atomic force microscope. In the sputter-grown amorphous films of various thicknesses at room temperature, we find the coexistence of α-Fe2O3 and Fe3O4 interfacial crystallites (~50-Å-thick), well aligned to the α-Al2O3[0001] direction. The amorphous precursor is crystallized to the epitaxial α-Fe2O3 grains in three steps with annealing temperature; i) the growth of the well aligned α-Fe2O3 interfacial crystallites to approximately 200-Å-thick, together with the transformation of the Fe3O4 crystallites to the α-Fe2O3 crystallites (< 400°C), ii) the growth of the less aligned α-Fe2O3 grains on top of the well aligned grains (> 400°C), and iii) the nucleation of the different less aligned α-Fe2O3 grains directly on the α-Al2O3 substrate (> 600°C). The surface evolution of the amorphous precursor films after annealing is consistent with the microstructure evolution during the crystallization.

A nanofabrication approach based on advanced e-beam lithography and electrodeposition successfully produced high-resolution (≈40 nm line width) metal structures with high aspect ratio (>12) and high density. The combination of these characteristics is essential for hard-x-ray optical components such as zone plates, for x-ray lithography masks and for other devices.

The authors describe an electroless deposition method for thin films, based on the irradiation by an x-ray beam emitted by a synchrotron source. Specifically, Ni–P films were deposited at room temperature. This synthesis is a unique combination of photochemical and electrochemical processes. The influence of the pH value on the formation and structural properties of the films was examined by various characterization tools including scanning electron microscopy, x-ray diffraction, and x-ray absorption spectroscopy. Real time monitoring of the deposition process by coherent x-ray microscopy reveals that the formation of hydrogen bubbles leads to a self-catalysis effect without a preexisting catalyst. The mechanisms underlying the deposition process are discussed in details.

Despite sufficient spatial resolution and routine operation, traditional electron microscopy (SEM and TEM) of polymer blend morphologies is limited to two dimensions (2D) and often requires tedious sample preparation. We have used a powerful X-ray imaging technique to visualize the morphology of polymer blends in three dimensions (3D). Images of polystyrene/high-density polyethylene (PS/HDPE) blend samples were constructed with microtomography using coherent synchrotron X-rays. Good contrast for blends with and without the PS phase removed (no other sample preparation was needed) was accomplished, and image quality is compared in the paper. High resolution (1 μm) images of relatively thick (∼1 mm) blend samples were possible by adapting a sample stage equipped with high precision motor controls, by enhancing phase contrast through optimization of sample−scintillator distance, and by taking a large number of projection images (up to 1000) along different angles. Reconstructed slices were used to create 3D ...

X-ray irradiation is shown to trigger the deposition of Cu from solution, at room temperature, on a wide variety of insulating substrates: glass, passivated Si, TiN/Ti/SiO2/Si and photoresists like PMMA and SU-8. The process is suitable for patterning and the products can be used as seeds for electroplating of thicker overlayers.

We have studied the low-temperature crystallization of (Ba⋅Pb) hexa-ferrite thin films using real time synchrotron X-ray scattering, anomalous X-ray scattering, and vibrating sample magnetometer. The crystallization temperature of amorphous (Ba⋅Pb) hexa-ferrite film (300-A-thick, ∼530∘C) was much lower than that of amorphous Ba hexa-ferrite film, ∼750∘C. The crystalline (Ba⋅Pb) hexa-ferrite phase was formed by solid phase transformation of the interfacial crystalline Fe3O4 phase through the diffusion of Ba or Pb cations. The low crystallization temperature of the (Ba⋅Pb) hexa-ferrite phase was due to the lower diffusion activation barrier of Pb cations than that of Ba cations. The small grain size (∼40 nm in diamter) and comparable magnetic properties (Ms ⊥: 337 emu/cm3, iHc ⊥ : 1.60 kOe) of the crystallized (Ba⋅Pb) hexa-ferrite film also demonstrate its potential possibility for high-density recording media.

We investigated the temperature dependence of growth mode in highly mismatched sputter-grown ZnO/Al2O3(0001) heteroepitaxial films using real-time synchrotron X-ray scattering. We find that the growth mode changes from 2 dimensional (2D) layer to 3D island in early growth stage with temperature (300∘C–500∘C). At around 400∘C, however, intermediate 2D platelets nucleate in early stage, act as nucleation cores of 3D islands and transform to misaligned state during further growth. The results of the strain evolution during growth suggest that the surface diffusion is a major factor in determining the growth mode in the strained ZnO/Al2O3(0001) heteroepitaxy.

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.

Three human liver tissue samples (~5 mm × 40 mm × 20 mm) were excised from a cancer patient's liver during surgery. The microradiology analysis was performed with a non-standard approach on a synchrotron. High-resolution refractive-index edge-enhanced microradio- graphs that cover a larger volume of the liver tissue sample were obtained. The cancer tissue and normal tissue could be clearly identified and distinguished based on their different textures. Furthermore, new blood vessel hyperplasia was found near the cancer area. Blood vessels with a diameter smaller than 20 μm could be identified. These findings were fully consistent with the histopathological examination of the same area. Microradiographs of the newly formed blood vessels at different angles were also obtained. This result shows that it is possible to further develop this approach into a technique of microradiographic imaging for clinic diagnosis of liver cancer at the early stage.

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.

We have developed a novel strategy for localized electrochemical deposition (LECD) to improve both the lateral resolution of the process and the porosity of the fabricated high-aspect-ratio microstructures. The strategy is based on accurately controlling the motion of the anode. Its implementation is made possible by the use of coherent, synchrotron X-ray microradiography with high time and lateral resolution, enabling the observation of the copper LECD process in real time. Microradiography reveals a deposition mechanism that differs as a function of the distance between the electrode (anode) and the growing structure (cathode). Specifically, the interplay of migration and diffusion of the metal ions in the baths affects the deposition rate and the characteristics of the fabricated structure. This enables us to optimize the anode motion control and greatly improve the quality of the structure grown.

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.

We describe the general characteristics and the first result of a new synchrotron beamline at the Pohang Light Source in Korea. The beamline, operated by a Korean-Taiwanese-Swiss consortium, is dedicated to microimaging experiment in real time with coherent x rays. The performances of the first tests already reach excellent levels when compared to other similar facilities worldwide. The key feature is the use of unmonochromatized x rays to achieve very high lateral and time resolution. (C) 2004 American Institute of Physics.

We have studied the interfacial diffusion of Fe/Cr multilayers using synchrotron X-ray techniques, such as X-ray reflectivity, extended X-ray absorption fine structures (EXAFS), and high-resolution X-ray scattering. The results of X-ray reflectivity indicated that the interfacial roughness of Fe/Cr multilayers increases with the Cr-layer thickness. The Fourier transform (FT) of EXAFS data clearly showed that the Fe atoms dominantly diffuse into the stable Cr layers at the Fe/Cr interface. The results of high-resolution X-ray scattering supported the interfacial diffusion of Fe atoms. Our study revealed that the dominantly interfacial diffusion of Fe atoms into the Cr layers effects the interfacial roughness of the Fe/Cr multilayers. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Growth behavior of Mn-doped ZnO thin films (Zn1-xMnxO) onAl2O3 (0001) substrates by pulsed laser deposition was investigated as a function of Mn content (0.00≤x≤0.35) mainly using synchrotron x-ray diffraction. We found that a small amount of Mn doping (x=0.05) significantly improves the crystalline quality, and also leads to a singly oriented film. The superior epitaxial growth of the film with an optimum Mn content seems to be associated with its microstructural evolution.

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.

The ramification of micropipes is observed using scanning electron microscopy, optical microscopy, and synchrotron x-ray radiography. The conditions for the ramification of dislocated micropipes are determined theoretically within a model when the angles between dislocation lines are small. It is shown that the ramification of micropipes into two smaller ones is possible only for micropipes with radii that exceed the equilibrium micropipe radius and is associated with a decrease in the total micropipe surface area.

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.

Ferromagnetism was found to coexist with superconductivity in Dy-doped BiPbSrCaCuO-2212 single crystals up to the superconducting critical temperature Tc ~ 80 K . Several experimental tests indicated that the phenomenon is intrinsic to the entire specimen rather than due to separate phases or to isolated impurities.

Accurate and versatile three-dimensional writing of individually controlled conducting polymer nanodevices forming dense arrays is demonstrated by guiding a monomer meniscus in pulling a micropipette during oxidative polymerization. We specifically demonstrate well-defined dense arrays of various freestanding nano-components with controlled radius down to similar to 50 nm: straight wires, nanowires with variable radius, branches, and bridges.

Light-emitting conjugated polymer nanowires are vertically grown and remotely manipulated into a freestanding straight or curved structure in three-dimension. This approach enabled us to eliminate substrate coupling, a critical issue in nanowire photonics in the past decade. We for the first time accomplished characterization of propagation and bending losses of nanowires completely decoupled from a substrate.

Microstructural changes in epitaxial SrRuO3 thin films grown on SrTiO3(001) during the early stages of growth by pulsed laser deposition were studied using synchrotron x ray scattering. We find that at a very early stage of growth (⩽110 A), the film is composed of a single (110) domain only, in sharp contrast to double (110) domains reported previously for thick (⩾1000 A) films. As the film grows further (>110 A), another, 90° rotated, (110) domain starts to form, coexisting with the original (110) domain. This domain evolution is attributed to strain relaxation, eventually resulting in significant atomic ordering in the in-plane direction.

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.

Ultra-high resolution radiographs can be obtained using synchrotron X-rays. A collaboration team consisting of K-JIST, POSTECH and YUMC has recently commissioned a new beamline (5C1) at Pohang Light Source (PLS) in Korea for medical applications using phase contrast radiology. Relatively simple image acquisition systems were set up on 5C1 beamline, and imaging studies were performed for resolution test patterns, mammographic phantom, and animals. Resolution test patterns and mammographic phantom images showed much better image resolution and quality with the 5C1 imaging system than the mammography system. Both fish and mouse images with 5C1 imaging system also showed much better image resolution with great details of organs and anatomy compared to those obtained with a conventional mammography system. A simple and inexpensive ultra-high resolution imaging system on 5C1 beamline was successfully implemented. The authors were able to acquire ultra-high resolution images for, resolution test patterns, mammographic phantom, fishes, and mice. The results showed that the 5C1 imaging system could be used for ultra-high resolution imaging studies in medical applications.

Epitaxial (Ba0.5,Sr0.5)TiO3 (BST) thin films have been grown on Si substrate with a very thin yttria-stabilized zirconia (YSZ) buffer layer by pulsed-laser deposition. The epitaxially grown BST thin films experienced lattice distortion along the in-plane direction due to the tensile stress induced primarily by thermal stress during deposition. Crystallinity and microstructures of a strained BST thin films have been closely investigated using X-ray diffractometer, transmission electron microscope, and synchrotron X-ray.

Microstructural changes in epitaxial SrRuO3 films grown on SrRuO3 (001) during early stages of growth by pulsed laser deposition were studied mainly using synchrotron x-ray scattering. At a very early stage of growth, the film is composed of a single (110) domain, in contrast to double (110) domains in later stages of growth. This domain evolution appears to be closely linked to a significant enhancement of crystalline ordering in the in-plane direction.

The thermal stability of RuO2/Si(100) films in air was studied using ex situ synchrotron x-ray scattering. The (110) textured RuO2 film showed good thermal stability due to the low surface and strain energies. However, the RuO2 films of high strain and surface energies were transformed to three-dimensional islands during annealing up to 800 °C. We also studied, during the post annealing process, the interface roughness of BaxSr1−xTiO3 (BST)/RuO2/Si(100) and BST/Pt/Ti/SiO2/Si(100) structures comparatively, using in situ synchrotron x-ray scattering. The interfaces of the BST/RuO2/Si were thermally stable up to 500 °C, and the deterioration of the interfaces above 500 °C was attributed to the crystallization of amorphous BST film. Meanwhile, the interfaces of the BST/Pt/Ti/SiO2/Si were significantly degraded even at the low temperature of 350 °C, mainly due to the formation of the Pt–Ti alloy and the Ti oxidation.

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.

The crystallization of Ba-ferrite/sapphire(001) films of various thicknesses has been studied using synchrotron x-ray scattering, field emission scanning electron microscope, and atomic force microscope. In films thinner than 1000 A, Ba-ferrite amorphous precursor was crystallized into perpendicular grains keeping the magnetically easy c-axis normal to the film plane during annealing to 750 °C. In films thicker than 1000 A, however, acicular grains keeping the c-axis parallel to the film plane were grown on top of the perpendicular grains. The behavior of the saturation magnetization and the intrinsic coercivity was consistent with the thickness dependence of the crystallization. We attribute the thickness dependence of the crystallization to the substrate effect, which prefers the growth of the epitaxial, c-axis oriented perpendicular grains near the film/substrate interfacial area.

Epitaxial (Ba0.5Sr0.5) TiO3 thin films of two different thickness (∼25 and ∼134 nm) on MgO(001) prepared by a pulsed laser deposition method were studied by synchrotron x-ray scattering measurements. The film grew initially with a cube-on-cube relationship, maintaining it during further growth. As the film grew, the surface of the film became significantly rougher, but the interface between the film and the substrate did not. In the early stage of growth, the film was highly strained in a tetragonal structure (c/a = 1.04) with the longer axis parallel to the surface normal direction. As the growth proceeded further, it relaxed to a cubic structure with the lattice parameter near the bulk value, and the mosaic distribution improved significantly in both in- and out-of-plane directions. The thinner film (∼25 nm) showed only one domain limited mainly by the film thickness, but the thicker film (∼134 nm) exhibited three domains along the surface normal direction.