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A new oxide, Bi(Mg1/2Ti1/2)O3 was prepared using a high-pressure high-temperature technique at 8 GPa and 1000°C. As-sintered Bi(Mg1/2Ti1/2)O3 has the BiFeO3-type perovskite structure with the rhombohedral R3c. After ground, crystal structure changed to tetragonal P4mm. Structure parameters of tetragonal Bi(Mg1/2Ti1/2)O3 were refined from laboratory X-ray powder diffraction data (a = 4.033(10) Å, and c = 3.938(10) Å). Bi(Mg1/2Ti1/2)O3 does not decompress at ambient pressure, but the structure changed from rhombohedral to tetragonal on heating above 800°C. This phase transition was nonreversible. Bi(Mg1/2Ti1/2)O3 is expected to be one of the end members of lead-free ferroelectric materials.

We have investigated the magnetic and dielectric properties of YbFe 2− x Mn x O 4 (0⩽ x ⩽1), which is an Fe-site-substituted system of new multiferroic oxides R Fe 2 O 4 ( R =Y, Ho–Lu). X-ray diffraction measurements show that a solid solution is formed between YbFe 2 O 4 ( x =0) and YbFeMnO 4 ( x =1) for 0⩽ x ⩽1, whereas only compounds with x =1 (i.e., RM 1 M 2 O 4 ; M 1 and M 2 =trivalent and divalent cations, respectively) have been known for the Fe-site substitution in R Fe 2 O 4 . The valence of the Mn ion is determined to be ∼2+, consistently with the suppression of low-temperature magnetization by the Mn substitution. The magnetic transition temperature ( T N ) and the dielectric constant ( e ′) decrease monotonically with increasing x . This result plausibly confirms that the magnetic and dielectric properties in oxides isostructural with R Fe 2 O 4 are governed by the electron transfer between Fe-site ions, unlike ordinary ferroelectrics and dielectrics, in which the ionic displacement plays a key role. The possibility for application is briefly discussed as well.

The magnetic and dielectric properties of perovskite manganites R 0.5 Ca 0.5 MnO 3 (R = Eu-Lu), which show charge ordering of the Mn-3d electrons below room temperature, have been investigated. Their dielectric constants were ∼ 1000–10000 at around room temperature. Inflections or peaks of temperature dependences of the dielectric constants were observed at around the charge-ordering temperatures. Analyses of tan δ for R = Eu-Lu and EXAFS spectra for R = Dy suggested that the dielectric properties of the present system are rooted in a special arrangement and transfer of the Mn-3d electrons. The two-peak structure of tan δ indicates that dielectric measurement can be used to observe homogeneity or inhomogeneity of sample, as mentioned in our previous paper on the ruthenium perovskite oxides.

Rare-earth iron oxides of the form RFe2O4 (R = Y, Ho–Lu) show a new mechanism of ferroelectricity owing to the charge ordering of Fe ions below ~330 K. To determine the physical properties of this system, the magnetic and dielectric properties of HoFe2O4 and R1-xR'xFe2O4 were investigated (R, R': rare earths). All the materials showed dielectric constants of ~1000–10000, as reported for some other RFe2O4 oxides. For HoFe2O4, magnetic ordering occurred at a temperature lower than those of RFe2O4 reported thus far. On the other hand, the dielectric measurements of this material suggested the development of a correlation between polar regions at higher temperatures, which was also observed for the Sc-substituted system Lu1-xScxFe2O4. These results encourage detailed investigations of these materials from the viewpoints of both fundamental and applied sciences, and suggest the existence of other new properties of RFe2O4.

Local structure analysis of (1-x)BiFeO3–xBaTiO3 mixture was carried out by a synchrotron radiation X-ray pair-distribution function (PDF) method. The PDF peak is resolved as a doublet owing to the presence of two phases with distinct local structures. The randomness of the off-center displacement of Bi atoms was different in these two phases, one was an average structure and the other a disordered rhombohedral structure. The volume fraction of each phase changed with BaTiO3 composition.

The magnetic and dielectric properties of InFe2O4, InFeCuO4, and InGaCuO4 have been investigated. All these materials are isostructural with RFe2O4 (R = Y, Ho-Lu), which shows ferroelectricity due to iron-valence ordering. InFe2O4 exhibits ferrimagnetic ordering at T(C) approximately 242 K and a dielectric constant (epsilon) of approximately 10,000 at around room temperature. These properties resemble those of RFe2O4; the origins of the magnetic and dielectric phenomena are likely common in InFe2O4 and RFe2O4. From measurements of the other two materials, we found that both T(C) and epsilon are decreased in the order of InFe2O4, InFeCuO4, and InGaCuO4. This result strongly supports the previously reported explanation based on an electron transfer between the Fe-site ions for the corresponding rare-earth systems. Therefore, we propose that the dielectric properties of the oxides isostructural with RFe2O4 are plausibly governed by electron transfer; this situation is different from that of ordinary ferroelectrics and dielectrics, in which the displacement of cations and anions is important. In addition, InFeCuO4 and InGaCuO4 exhibit large epsilon values (epsilonapproximately 1500). In consideration of this property, we discuss the possible applications of these oxides.

We performed synchrotron X-ray topography on a La3Ta0.5Ga5.5O14 (LTG) crystal grown by the Czochralski method. Since a synchrotron X-ray source can provide high-energy X-rays, one can detect bulk structures by X-ray topography. LTG is one of the most attractive piezoelectric crystals along with La3Ga5SiO14 (LGS) because of its excellent acoustic properties (temperature compensation of acoustic losses). Since LTG single crystals can be grown from a stoichiometric melt, it was expected that single crystals with better quality than the LGS crystal, which cannot be grown from a stoichiometric system but only from a congruent melt, can be obtained. However, 60 keV X-ray topography revealed that the LTG crystal quality was not as high as the LGS crystal quality. The crystal quality of the central region was lower than that of the surrounding region.

We observed all-in type Nb tetrahedral displacement in nonmagnetic pyrochlore niobates ${A}_{2}{\mathrm{Nb}}_{2}{\mathrm{O}}_{7}(A={\mathrm{Nd}}_{0.5}{\mathrm{Ca}}_{0.5}$ and ${\mathrm{Y}}_{0.5}{\mathrm{Ca}}_{0.5})$ through the analysis of the neutron pair distribution function and the extended x-ray absorption function spectroscopy. The all-in type Nb tetrahedral displacement, which has the character of a charge singlet state, is driven by the formation of the bonding orbital. The diffuse scattering in the x-ray diffraction, which has the resonant component in the Nb ${L}_{3}$ edge, indicates that the all-in type Nb tetrahedral displacement has the periodicity with its short-range correlation.

The langasite (La3Ga5SiO14, LGS) crystal grown by the Czochralski technique was investigated by X-ray diffraction measurements. The X-ray diffraction profiles of the LGS consisted of sharp Bragg peaks and large amounts of diffuse scatterings. The diffuse scatterings indicated the existence of a local structure, which is different from the average structure of LGS. The local structure was analyzed by the pair-distribution function method. The local structure fluctuated owing to the local disordering of La atoms.

The magnetic and dielectric properties of a perovskite manganite Tb0.5Ca0.5MnO3 were investigated. Magnetic measurements showed three characteristic temperatures, originating from charge ordering (~300 K), antiferromagnetic ordering (~120 K), and a transition to a glassy state (~50 K). The coexistence of the charge and antiferromagnetic orderings was confirmed by powder neutron diffraction. AC dielectric measurements showed large dielectric constants larger than ~1000 at approximately room temperature. The temperature dependence of the dielectric constant changed just below the charge-ordering temperature. From the analysis of tan δ, the activation energy for switching the directions of polar regions was calculated to be ~0.09 eV, which is close to the activation energy of the Mn 3d electron transfer. These results strongly suggest that the dielectric properties of this material are governed by the ordering and transfer of the Mn 3d charges.

Bi 0.9− x La 0.1 Tb x FeO 3 with x = 0.0 and 0.075 were synthesized by the solid-state reaction. Although it was difficult to obtain pure BiFeO 3 with single phase, the La-substituted Bi 0.9 La 0.1 FeO 3 can be obtained easily without any impurity phase. The Tb-substituted Bi 0.825 La 0.1 Tb 0.075 FeO 3 showed a well-saturated ferromagnetism. The average and local structures of the Bi 0.9 La 0.1 FeO 3 and Bi 0.825 La 0.1 Tb 0.075 FeO 3 crystals were analyzed by Rietveld refinement and pair-distribution function (PDF) method, respectively. The La and Tb atoms were completely substituted for the Bi, and lattice strain owing to different ionic radii was relaxed only by the bond distribution between the A-site atoms and the oxygen atoms.

The purposes of this study are to construct a simple dioxin detection system using peptides that bind to dioxin, and to test the system on real environmental samples. In this method, dioxin and N-NBD-3-(3',4'-dichlorophenoxy)-1-propylamine (NBD-DCPPA) are competitively bound to the peptides synthesized on beads. The fluorescence intensity of the bead decreases with increasing dioxin concentration. The concentration of dioxin is determined by measuring the fluorescence intensity using a fluorescence microscope equipped with a CCD camera. The fluorescence microscope system was equipped with a motor-driven stage and could be used with 96-well microplates and analytical software that automatically measured the fluorescence intensity of the bead images in the wells. Dioxin detection conditions, reaction temperature, number of beads and concentration of the organic solvent were optimized. About 0.5 nM (150 pg mL(-1)) of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TeCDD) could be detected under the optimized conditions. Environmental soil samples were subjected to the detection system using the peptide beads. Although the results obtained correlated poorly with the toxicity equivalency quantity (TEQ) concentration obtained by a GC/MS method, our method is robust enough as a prescreening method to detect at least 250 pg-TEQ g(-1), the survey level for soil as stipulated in the law concerning special measures against dioxins in Japan.

(Bi1 − x La x )FeO3 with x = 0.00, 0.05, 0.10 and 0.20 were synthesized by the solid-state reaction. The reaction parameters such as calcined temperature was optimized in order to obtain single-phase (Bi1 − x La x )FeO3. The magnetic and ferroelectric transition temperatures were evaluated by thermal analysis. Both magnetic and ferroelectric phase-transition temperature of the (Bi1 − x La x )FeO3 samples shifted to lower temperature than that of the pure BiFeO3 as the lanthanum concentration increased, but the temperature shifts were much smaller than those of previous reports.

In ferroelectrics, it is sometimes observed that the local structure is different from the average structures. We observed the difference between the local and average structure of Bi4Ti3O12. The average and local structures were refined by Rietveld and Pair-distribution function (PDF) analysis, respectively. These were refined with the same data set collected by high-energy synchrotron X-ray diffraction. The crystal symmetry of both the local and average structures of Bi4Ti3O12 was orthorhombic. The TiO6 rotation angle around the b-axis of the local structure was larger than that of the average structure. The difference should originate from oxygen vacancies, which are generated in crystal synthesis.

High-energy synchrotron X-ray measurements (HEXRD) and pair-distribution function (PDF) analysis were carried out to investigate the local structure in ferroelectric Cd 1−x Zn x Te alloy. The Cd 1−x Zn x Te crystallizes in the zinc-blende structure and the PDF analysis revealed that the zinc-blende lattice of the Cd 1−x Zn x Te alloy distorts locally to accommodate the distinct Cd-Te and Zn-Te alloy bond lengths. The local disorder correlate in the ⟨111⟩ direction and it is the origin of macroscopic ferroelectricity in the Cd1−x Zn x Te alloy.

A glass sample of composition Bi 4 Ti 3 O 12 was prepared by rapid quenching. The as-quenched sample was confirmed to be amorphous by synchrotron X-ray measurements. The crystallization process of the amorphous sample was also investigated by high-energy X-ray diffraction and by atomic pair distribution function analysis. The perovskite layer in the crystal Bi 4 Ti 3 O 12 is transformed to a pyrochlore structure in the amorphous sample. The amorphous sample first crystallized to a metastable phase by acquiring long-range ordering of the pyrochlore structure at T cryst1 , and then secondary crystallized into a reverted Bi 4 Ti 3 O 12 structure at T cryst2 .

The use of high-energy (E ≥ 50 keV) X-rays from SPring-8 allows us to perform X-ray diffraction experiments on disordered materials with the following advantages: high resolution in real space due to the wide range of scattering vector, small correction terms (particularly the absorption correction), and fast diffraction measurement with small amount of samples. Recently, high-energy X-ray diffraction data have been combined with neutron diffraction data from a pulsed neutron source to provide more detailed and reliable structural information than has hitherto been available. Furthermore, the use of reverse Monte Carlo modelling and PDF (pair distribution function) simulation based on high-energy X-ray diffraction data have succeeded in illustrating 3-dimensional structure of disordered materials and disorder in crystalline materials.

The GaAs(0 0 1)-( 2 × 4 ) reconstructed surface was investigated by in situ surface X-ray diffraction. X-ray diffraction patterns were measured with increasing substrate temperature within the β phase of GaAs(0 0 1)-( 2 × 4 ) in a constant As flux of 5 × 1 0 − 7 Torr. At relatively low temperatures up to 545 ∘C, the observed X-ray diffraction patterns agree well with the β 2( 2 × 4 ) surface. However, a different X-ray diffraction pattern was obtained at temperatures close to the α phase, while the 2 × 4 periodicity still persisted. This change is explained by partial As-dimer desorption which results in a mixture of the β 2( 2 × 4 ) and α 2( 2 × 4 ) structures.

We have observed 90° domain walls in a bulk BaTiO 3 crystal by synchrotron radiation topography, coupled with a CCD detector. The BaTiO 3 multi-domain crystal was revealed to be strained at the 90°...

The dynamics of the molecular-beam-epitaxy (MBE) of GaAs (0 0 1) was investigated with a surface X-ray diffractometer coupled to an MBE chamber. The diffracted intensity of X-rays was measured in real time during growth. The temporal oscillation of the intensity for the growth at 550°C was explained well by the distributed-growth model, while the intensity for the growth at 435°C showed a complicated behavior arising from the changes in the surface reconstruction and the morphology. A method for separating the dynamics of the morphology from that of the reconstruction is presented.

Ferroelectric BaTiO 3 thin films with a thickness of 10 monolayers (ML) were epitaxially grown on SrTiO 3 (0 0 1) substrates by very slow deposition using molecular beam epitaxy (MBE). The investigations were carried out by two growth methods: (i) codeposition and (ii) alternate deposition of the metal elements in an oxygen atmosphere. In situ observation of reflection high-energy electron diffraction confirmed that an epitaxial cube-on-cube structure was prepared. After the deposition, X-ray diffraction measurements were carried out. The 10-ML-thick BaTiO 3 films were highly c -axis oriented single crystals with good film quality.

Thermal properties of ordered and disordered Pb(In1/2Nb1/2)O3 (PIN) single crystals were investigated. For the ordered PIN, typical thermal anomalies were observed at the antiferroelectric transition temperature. These anomalies were degraded and disorder appeared during heating processes. The defect-induced phase separation provided a good account of the instability of the relaxor and antiferroelectric states of the PIN crystals.

An X-ray diffractometer connected with a molecular-beam epitaxy (MBE) system has been constructed for in situ studies on the growing surfaces of III–V compound semiconductors. This diffractometer is based on the (4+2) type, which has four axes for orienting the sample and two axes for positioning the detector. In addition, it is equipped with an axis for rotating the receiving slit about the normal of the slit plane to align the resolution of the receiving slit properly for the surface X-ray diffraction measurement. For the alignment of the sample and the entire setup with respect to the X-ray beam, an XYZ-stage and an adjustable base plate are available. X-rays enter and leave the chamber through two Be windows welded directly to the MBE chamber. A graphite sheet which can be heated up to 250°C is placed along the inside of the Be windows to protect the Be windows from being coated with evaporated materials. Preliminary data are presented to demonstrate the feasibility of static and dynamic measurements of growing surfaces using this instrument.

Semiconductive cadmium telluride and zinc telluride mixture (Cd 1 m x Zn x Te) is observed to have ferroelectric behaviors such as the D-E hysteresis measurements, dielectric measurements and thermal measurements that suggest the existent of ferroelectric phase transition. The paraelectric structure in high-temperature phase is zinc-blende structure. An order-disorder type phase transition occurs and the structure of Cd 1 m x Zn x Te crystal changes to ferroelectric pseudo cubic structure. However, the detail of the mechanism of the phase transition and the structure of ferroelectric phase have not been revealed. We performed X-ray diffraction measurements with synchrotron radiation and obtained a clear evidence of short range order or intermediate range order structure in ferroelectric phase. The role of glassy structure in the mechanism of ferroelectric behavior is discussed.

A monoclinic ferroelectric phase with the space group Pm has been discovered in lead-free (Na0.5K0.45Li0.05)NbO3 solid solution ceramics synthesized by a malic acid complex solution method. At ambient temperature, the lattice parameters of this monoclinic structure were . The average and local structures of this monoclinic phase were analyzed by synchrotron X-ray measurements. The average structure maintained the monoclinic structure down to 20 K, although the local structure changed below room temperature. The distinct short-range order structure was found to be rhombohedral. The results demonstrate the presence of an order?disorder-type phase transition structurally bridging between the rhombohedral local structure and the low-symmetry monoclinic average structure in a (Na0.5K0.45Li0.05)NbO3 solid solution system.

The hydrogenation process of aluminum, especially pulverization of aluminum prior to the hydrogenation reaction was investigated by in situ synchrotron radiation X-ray diffraction measurements at high pressure and high temperature. Changes in the crystal grain sizes during the hydrogenation process were observed using the angle dispersive method, while weak Bragg peaks from aluminum and AlH3 with small X-ray scattering factors were detected using focused monochromatic X-rays as the incident beam. The in situ measurement system monitored the pulverization of aluminum at several pressure-temperature conditions where AlH3 was thermodynamically stable.

The phase transition of ferroelectrics is one of their most important bulk-nature attributes. In well-epitaxial ferroelectric thin films, the crystal structures are highly strained and the ferroelectric phase transitions tend to dissappear because of an epitaxial effect. We investigated the epitaxial effect by structural analysis and clarified the growth conditions of BaTiO3 films that show their bulk nature. As a result, epitaxial crystals of BaTiO3 with a thickness of 67 A were grown on a MgO substrate with a Pt electrode by the activated reactive evaporation method. A clear thermal anomaly was observed at 140 °C that suggests the phase transition of BaTiO3.

A systematic alignment method is described for fixed-exit position operation of SPring-8 standard monochromator in rotated-inclined geometry. Results of high-heat-load test showed the water-cooled pin-post crystal combined with the geometry well surpass 400 W/mm 2 power density of the X-ray undulator radiation.

Bi0.95La0.05FeO3 were synthesized by the solid-state reaction. Bi0.95La0.05FeO3 showed variety of crystallinity depending on the synthesized condition. The average and local structures of the Bi0.95La0.05FeO3 crystals were analyzed by Rietveld refinement and pair-distribution function method, respectively. Although the average structure does not depend on the synthesized condition, the mosaic block size of the Bi0.95La0.05FeO3 crystals were changed by the synthesized condition. The difference of the mosaic block size is a cause of the different thermal properties.

Epitaxial crystals of BaTiO3 with thickness of 67 A were grown on MgO substrate with a Pt electrode by the activated reactive evaporation method. The lattice parameter was characterized by x-ray diffraction. The tetragonality of the crystal was much higher than that of the bulk crystal and the growth layer was strained by the epitaxial effect. Thermal measurements were performed to clarify the phase transition of the thin crystal. A clear thermal anomaly was observed at 140 °C that suggests a phase transition of BaTiO3. This is the first observation of a phase transition of such a thin crystal of BaTiO3. We discuss the requirements for a phase transition in terms of the epitaxial effect.

JAERI Group has constructed three beamlines for carrying out their own research at SPring-8. One of the three is the bending magnet Beamline for the purpose of materials research. We will describe here the feature of the beam line and the spectrometer, and also some data which have been recently taken at this beamline.

We have observed cylindrical 180° domains and 90° multi-domains in crystalline films by an atomic force microscope and in bulk crystals by a scanning electron microscope. The size distribution of the 180° domain end is determined graphically by a computer analysis. A discussion is given on why a thickness dependence of the end size coincides with the theoretical relation proportional to the square root of the thickness over a wide range from 4 nm to 1.4 mm and why the 90° domain is found only in a film of a particular thickness.

We have fabricated n-UCT SrRuO3/SrTiO3 superlattices, [SrTiO3 5-UCT/SrRuO3 n-UCT]m (n=1∼20), where UCT is a unit-cell thickness, on SrTiO3(001) substrates to study a low-dimensional structural effect on the magnetic properties of SrRuO3. We measured temperature-dependent and field-dependent magnetization. The ferromagnetic transition temperature decreased with decreasing n, and the transition vanished for n=1. A strong anisotropy of magnetization with an easy axis perpendicular to the film plane was observed for all the samples, as seen in SrRuO3 thin films on SrTiO3(001) substrate. The in-plane magnetization was extremely suppressed as n decreased. For 3-UCT superlattice, the in-plane magnetization became 1/10 of the out of plane magnetization at T=5 K and H=1 T. The role of low-dimensionality between SrRuO3 and SrTiO3 on magnetism of SrRuO3 is discussed.

Epitaxial ultrathin films of BaTiO3 were prepared using molecular beam epitaxy. For the substrate, (001)-oriented SrTiO3 single crystals were used. Controlling the growth conditions of these films as well as the semiconductor thin films, led to the successful growth of the BaTiO3 films as single crystals, characterized by x-ray diffraction even in the ultrathin range. The ultrathin BaTiO3 films are highly c-axis-oriented tetragonal phaselike bulk BaTiO3 crystals. The tetragonality of the thin film crystals is much larger than bulk crystal’s. We also measured the saturated polarization (Ps) of the BaTiO3 films at temperatures ranging from room temperature to 600 °C. The results confirmed again that the films are ferroelectric tetragonal phase crystals. Moreover, they showed that the transition temperature for the ferroelectric-paraelectric phase transition of the films is higher than bulk crystal’s.

Polyimides are widely used as dielectrics in high density multi-chip module (MCM) wiring systems in order to adjust the thermal expansion between LSI chips and substrates. In these MCMs, Copper is commonly used for vias which interconnects different layers. In these structures, there are some drawbacks which adversely affect the multi-layer wiring system. Among them, a major problem is that in order to get a high wiring density, a large number of vias with a very small via diameter have to be created. However, if there are large number of vias, due to the Z-directional thermal expansion mismatch of Cu and the dielectric, stress concentrated around vias leading to fracture and crank formation in the dielectric. Therefore, in this paper, in order to find a promising dielectric material, to the utilized in MCMs, the Z-directional coefficient of thermal expansion (CTE) of polyimide films prepared with different processing conditions was investigated. The Z-directional CTE of the films was measured by the laser interferometric technique.

Magnetotransport properties of an 80 nm-thick high quality epitaxial film of SrRuO 3 grown on SrTiO 3 (001) were investigated. The film has tetragonal structural symmetry ( c -axis ⊥ film plane), and shows a uniaxial strong magnetic anisotropy with the easy axis along the c -axis. Magnetotransport phenomena are also uniaxially anisotropic. Magnetoresistivity, Δρ x x ( H ), in longitudinal geometry is negative and becomes larger at T C . The Hall resistivity, ρ x y ( H ), is not proportional to magnetic field because it contains the extraordinary Hall resistivity component, which is composed of negative skew scattering and positive side-jump scattering, both of which are due to spin-orbital interaction. The field-dependence of ρ x y ( H ) indicates that the origin of Δρ x x ( H ) of SrRuO 3 is the spin-dependent scattering. The ordinary Hall coefficient depends on temperature in such a way that, among multi carriers electron type carriers become dominant below T C .

The effect of two novel diffusion protective coating methods for Cu/polyimide interface, chromate treatment and 1H-tetrazole addition, have been investigated. The protective coating layer of chromate was less than a few nm thick. The Cr structure of the chromate film was assigned as Cr-oxide. 1H-tetrazole which was added into the polyamic acid was effective inhibitor for Cu/polyamic acid reaction. We have confirmed that our protective coatings, the chromate treatment and 1H-tetrazole addition, prevented the Cu diffusion into the polyimide films. Both of these protective coatings are effective and practical from an application point of view.