We have found a new route for preparing Pt containing perovskites. Ba containing perovskite powder, (La0.7Sr0.2Ba0.1)ScO3–δ (LSBS), reacted with Pt foil at 1898 K in air, and formed ultramarine colored Pt containing perovskite, (La0.7Sr0.2Ba0.1)(Sc,Pt)O3–δ, without changing the GdFeO3-type structure. The chemical compositions of the samples before and after firing, measured with inductively coupled plasma (ICP) optical emission spectrometry, were La: Sr: Ba: Sc = 0.70(1): 0.206(4): 0.101(2): 0.98(2) and La: Sr: Ba: Sc: Pt = 0.70(1): 0.197(4): 0.085(2): 0.95(2): 0.0062(2), respectively. The reaction proceeded not only at the interface between perovskite powder and Pt foil, but also over whole powder surface. We name this new preparation method the “solid-phase elution (SE) method”, because the process involves elution of Pt ions from the Pt foil to the LSBS perovskite lattice. It is expected that we can control the amount of Pt introduced into perovskites by using the SE method after optimizing the reaction time and temperature.

We studied the effects of the sintering temperature and applied pressure on Nd–Fe–B bulk nanocomposite magnets produced by the spark plasma sintering (SPS) method. Amorphous Nd4Fe77.5B18.5 melt-spun ribbons were successfully consolidated into bulk form by the SPS method. When sintered at 873 K under applied pressures between 30 and 70 MPa, the bulk materials consisted of nanocomposite materials with a soft magnetic Fe3B phase and hard magnetic Nd2Fe14B phase. The density and magnetic properties of the bulk materials sintered at 873 K were strongly dependent on the applied pressure during sintering. Bulk Nd4Fe77.5B18.5 nanocomposite magnets sintered at 873 K under an applied pressure of 70 MPa showed a high remanence of 9.3 kG with a high coercivity of 2.5 kOe.

Composite dielectric ceramics of BaTiO3/SrTiO3 were prepared using the spark plasma sintering (SPS) method. Relatively dense (>92% of the theoretical x-ray density) composite ceramics were obtained for a relatively short sintering time (∼3 min). Such a short sintering time was advantageous in suppressing the formation of a complete solid solution (Ba, Sr)TiO3. Fixed-frequency (100 kHz), room-temperature permittivity measurements of the BaTiO3/SrTiO3 = 9/1 composites showed a flat temperature dependence within the range 30–110 °C. X-ray diffractometry measurements showed that the current SPS-BaTiO3/SrTiO3 composites consisted of BaTiO3 and small amounts of (Ba1−xSrx)TiO3 with various x values having different phase transition temperatures. Such multicomponent microstructures would be responsible for the flat temperature dependence of permittivity.

The valence and coordination structure of implanted Cu and Br ions were investigated by x-ray absorption fine structure spectroscopy in (2.4 MeV 6 × 1016 Br2+ ions cm−2+ 2 MeV 6 × 1016 Cu+ ions cm−2)-implanted silica glass. It was found that the implanted Cu and Br atoms were coordinated by oxygen atoms and silicon atoms, respectively, in as-implanted glass. After heating at 600 °C, at least two-thirds of the Cu atoms were coordinated by Br atoms without the formation of crystals. The γCuBr crystal was formed after heating to 1100 °C. It was deduced that the coordination structure of Cu and Br atoms depends on defects as well as thermochemical stability and mass transport processes.

Structure of Cu ions in (Cl+Cu)-, (Br+Cu)-, (I+Cu)-, (S+Cu)- and (Se+Cu)-ion implanted silica glasses has been studied by x-ray absorption and optical absorption spectroscopies. Cu ions formed Cu-O bonds in the as-implanted glasses, due to the homogeneous distribution of Cu ions and the low local concentration of halogen and chalcogen ions in silica glass. Heat treatment at about 600°C caused the formation of bonds between Cu ions and halogen/chalcogen ions without forming Cu halide or chalcogenide crystals. It was deduced that the formation of these bonds was controlled by the diffusion of Cu ions in silica glass. On the other hands, it was inferred that the formation of Cu halide and chalcogenide crystals was controlled not only by the diffusion of halogen/chalcogen ions but also by the diffusion of matrix ions.

Dense BaTiO3 ceramics consisting of fine grains were prepared using fine powder (average grain size of 0.06 μm; BT006) as a starting material and the spark plasma sintering (SPS) method. The powder was densified to >95% of theoretical x-ray density by the SPS process, and the average grain size of the resulting ceramics was <0.5 μm; the particle size of the initial powder significantly affects the grain size of the resulting SPS pellets. Fixed-frequency (100 kHz), room-temperature permittivity measurements of the BT006-SPS ceramics showed relatively low values (3000–3500) compared with those (typically 5000) for SPS ceramics consisting of larger grains (approximately 1 μm). Lower permittivity was attributed to poor development of ferroelectric domains in the ceramics, which originated from incomplete development of the tetragonal structure as well as the presence of a local orthorhombic structure.

Coordination structures of implanted Fe, Co, and Ni ions were studied in 1.78–2.00-MeV 5 × 1016 ions/cm2-implanted silica glasses by x-ray absorption and optical absorption spectroscopies. It was found from x-ray absorption spectra that the implanted Fe, Co, and Ni ions are coordinated by ca.3 oxygen atoms. The implanted ions dispersed in glass matrix and did not form crystals. The valence of the implanted ions was about 1.5. The Fe–O, Co–O, and Ni–O interatomic distances were 190, 191, and 192 pm, respectively. In addition, it was found from optical absorption spectra that one-fifth of implanted Co ions were present as Co2+ ions in tetrahedral symmetry.

180 keV Mn+ ions were implanted in silica glass at doses ranging from 1×1016 to 2×1017 ions/cm2 at room temperature. The coordination structure of implanted Mn atoms was studied by X-ray absorption spectroscopy. It was found that Mn atoms were mainly coordinated by O atoms in silica glasses as-implanted at doses lower than 5×1016Mn+ions/cm2. The Mn-O bond distance was 2.07 Å and the coordination number was 4.3 in average. Mn atoms were mainly coordinated by Mn and O atoms in the glasses as-implanted at doses higher than 1×1017 Mn+ions/cm2. In all the glasses, Mn atoms which are coordinated by O atoms were present as divalent state. After heating at 700 °C in air, Mn atoms were present as trivalent state and tended to form oxide crystals.

Coordination state of gold atoms implanted in silica glass to an energy of 1.5 MeV and a dose of 1 × 1017 ions/cm2 has been studied by x-ray absorption fine structure spectroscopy. It was found that most of the gold atoms form gold clusters in which the nearest neighboring Au–Au interatomic distance is shorter by 0.05 °A than that in bulk gold. The contraction of Au–Au interatomic distance of gold clusters in silica glass is less than that reported in the previous studies on gold clusters within the other substrates. Gold atoms are coordinated by about four gold atoms in average. In addition, it was found that Au–O bonds are formed at the gold clusters/silica glass interface. It was deduced that the formation of Au–O bond at the gold clusters/silica glass interface depresses the contraction of Au–Au interatomic distance.

The local structure and crystallization behavior of Nd15Fe77Bx (x = 2−14) melt-spun alloys were studied by Nd L3 extended x-ray absorption fine structure (EXAFS). The conventional x-ray powder diffractometry studies showed that the Nd–Fe–B melt-spun ribbons had the amorphous structure regardless of the boron content. EXAFS studies of the local structure around the Nd atom confirmed that the Nd–Fe–B melt-spun alloys had the amorphous structure and virtually the same nearest neighbor distance from the Nd atom. The amorphous alloys were heated by a differential scanning calorimetry in order to investigate the variation in the local structure during the crystallization process by EXAFS measurements. Although no appreciable difference was found in the nearest neighbor distance of the Nd atom between the amorphous alloys and the crystallized alloys, the small variation in the nearest neighbor distance during the crystallization process was detected by EXAFS measurements.

The structure of ultrafine gold particles embedded in silica glass by ion implantation has been studied by x-ray absorption fine structure spectroscopy. It is found that the Au–Au interatomic distance in the particles is very similar to that in bulk gold within 0.01 Å. Mean-square relative displacement in the particles is 1.2–1.3 times larger than that in bulk gold.