a

Language：English   Publishing type：Research paper (scientific journal)  

Water splitting using a semiconductor photocatalyst has been extensively studied as a means of solar-to-hydrogen energy conversion. Powder-based semiconductor photocatalysts, in particular, have tremendous potential in cost mitigation due to system simplicity and scalability. The control and implementation of powder-based photocatalysts are, in reality, quite complex. The identification of the semiconductor-photocatalytic activity relationship and its limiting factor has not been fully solved in any powder-based semiconductor photocatalyst. In this work, we present systematic and quantitative evaluation of photocatalytic hydrogen and oxygen evolution using a model strontium titanate powder/aqueous solution interface in a half reaction. The electron density was controlled from 10¹⁶ to 10²⁰ cm^-3 throughout the strontium titanate powder by charge compensation with oxygen nonstoichiometry (the amount of oxygen vacancy) while maintaining its crystallinity, chemical composition, powder morphology, and the crystal and electronic structure of the surface. The photocatalytic activity of hydrogen evolution from aqueous methanol solution was stable and enhanced by 40-fold by the electron doping. The enhancement was correlated well with increased Δabsorbance, an indication of prolonged lifetime of photoexcited electrons, observed by transient absorption spectroscopy. Photocatalytic activity of oxygen evolution from aqueous silver nitrate solution was also enhanced by 3-fold by the electron doping. Linear correlation was found between the photocatalytic activity and the degree of surface band bending, ΔΦ, above 1.38 V. The band bending, potential downhill for electronic holes, enlarges the total flux of photoexcited holes toward the surface, which drives the oxygen evolution reaction.

DOI： 10.1021/acscatal.8b01379

Language：English   Publishing type：Research paper (scientific journal)  

Solar-driven thermochemical water splitting using non-stoichiometric oxides has emerged as an attractive technology for solar fuel production. The most widely considered oxide for this purpose is ceria, but the extreme temperatures required to achieve suitable levels of reduction introduce challenges in reactor design and operation, leading to efficiency penalties. Here, we provide a quantitative assessment of the thermodynamic and kinetic properties of La _1-xSr_xMnO_3-δ perovskites, targeted for a reduced temperature operation of thermochemical water splitting. Sr-doping into lanthanum manganite increases the thermodynamic fuel production capacity, which reaches 9 ml g^-1 for 0.4 Sr for a thermochemical cycle operated between 1400 and 800 °C. The hydrogen yields are moreover in good agreement with expected values based on analysis and extrapolation of thermogravimetric data available in the literature. High levels of Sr doping, however, result in low steam-to-hydrogen conversion rates, implying high energy penalties in an operational reactor. Furthermore, the rate of fuel production decreases with increasing Sr content, suggesting that intermediate compositions may yield the most suitable combination of properties. This journal is

DOI： 10.1039/c4ta02694b

Language：English   Publishing type：Research paper (scientific journal)  

The environmental benefits of fuel cells have been increasingly appreciated in recent years. Among candidate electrolytes for solid-oxide fuel cells, yttrium-doped barium zirconate has garnered attention because of its high proton conductivity, particularly in the intermediate-temperature region targeted for cost-effective solid-oxide fuel cell operation, and its excellent chemical stability. However, fundamental questions surrounding the defect chemistry and macroscopic proton transport mechanism of this material remain, especially in regard to the possible role of proton trapping. Here we show, through a combined thermogravimetric and a.c. impedance study, that macroscopic proton transport in yttrium-doped barium zirconate is limited by proton-dopant association (proton trapping). Protons must overcome the association energy, 29 kJ mol -1, as well as the general activation energy, 16 kJ mol -1, to achieve long-range transport. Proton nuclear magnetic resonance studies show the presence of two types of proton environment above room temperature, reflecting differences in proton-dopant configurations. This insight motivates efforts to identify suitable alternative dopants with reduced association energies as a route to higher conductivities.

DOI： 10.1038/nmat3638

Language：English  

Language：English   Publishing type：Research paper (scientific journal)  

Barium zirconate has attracted particular attention among candidate proton conducting electrolyte materials for fuel cells and other electrochemical applications because of its chemical stability, mechanical robustness, and high bulk proton conductivity. Development of electrochemical devices based on this material, however, has been hampered by the high resistance of grain boundaries, and, due to limited grain growth during sintering, the high number density of such boundaries. Here, we demonstrate a fabrication protocol based on the sol - gel synthesis of nanocrystalline precursor materials and reactive sintering that results in large-grained, polycrystalline BaZr _0.8Y _0.2C _3-δ of total high conductivity, ∼ 1 × 10 ^-2 Scm ^-1 at 450 °C. The detrimental role of grain boundaries in these materials is confirmed via a comparison of the conductivities of polycrystalline samples with different grain sizes. Specifically, two samples with grain sizes differing by a factor of 2.3 display essentially identical grain interior conductivities, whereas the total grain boundary conductivities differ by a factor of 2.5-3.2, depending on the temperature (with the larger-grained material displaying higher conductivity).

DOI： 10.1021/cm900208w

Language：English   Publishing type：Research paper (scientific journal)  

Thermogravimetry has been used to evaluate the equilibrium constants of the water incorporation reaction in yttrium-doped BaZrO₃ with 20-40% yttrium in the temperature range 50-1000°C under a water partial pressure of 0.023 atm. The constants, calculated under the assumption of a negligible hole concentration, were found to be linear in the Arrhenius representation only at low temperatures (≤500 °C). Nonlinearity at high temperatures is attributed to the occurrence of electronic defects. The hydration enthalpies determined here range from -22 to -26 kJ mol^-1 and are substantially smaller in magnitude than those reported previously. The difference is a direct result of the different temperature ranges employed, where previous studies have utilized higher temperature thermogravimetric measurements, despite the inapplicability of the assumption of a negligible hole concentration. The hydration entropies measured in this work, around -40 J K^-1 mol ^-1, are similarly smaller in magnitude than those previously reported and are considerably smaller than what would be expected from the complete loss of entropy of vapor-phase H₂O upon dissolution. This result suggests that substantial entropy is introduced into the oxide as a consequence of the hydration. The hydration reaction constants are largely independent of yttrium concentration, in agreement with earlier reports.

DOI： 10.1021/cm800843s

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1246/cl.200835

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1246/cl.200942

Language：English   Publishing type：Research paper (scientific journal)  

Dye-sensitized solar cells and photocatalysts that consist of a light-absorbing dye and a wide gap oxide semiconductor substrate have been studied extensively as a means of solar energy conversion. Although defects existing at an oxide surface have a significant impact on the electron injection efficiency from the excited state dye-molecule into the oxide, the effects of defects on the electron injection process have not been fully understood in any dye-sensitized system. In this study, we present a systematic evaluation of electron injection into defects using emissive Ru(II) complexes adsorbed on oxide substrates (HCa₂Nb₃O₁₀ nanosheets and nonstoichiometric SrTiO_3-δ), which had different defect densities. Using these oxides, electron injection from adsorbed Ru(II) complexes was observed by time-resolved emission spectroscopy. It was shown that electron injection from the excited state Ru(II) complex into an oxide was influenced by the defect density of the oxide as well as by the excited state oxidation potential (E_ox*) of the Ru(II) complex. Electron injection was clearly accelerated with increasing defect density of the oxide, and was inhibited with increasing electron density of the oxide because of a trap-filling effect. Even though the E_ox∗ of the Ru(II) complex was more positive than the conduction band edge potential of the oxide, electron injection into defects could be identified when a defective oxide was employed. The electron injection event is discussed in detail, on the basis of the defect density and the energy levels of oxides as well as the E_ox∗ values of the Ru(II) complexes. Overall, the results suggest that it is possible to estimate the potential of surface defect states in oxide by changing E_ox∗ of an emissive complex dye.

DOI： 10.1021/acs.jpcc.9b09781

Language：English   Publishing type：Research paper (scientific journal)  

We report on current-induced ferromagnetic resonance techniques to characterise spin-Hall effect at high temperatures. A microwave current was injected into a patterned CoFeB/Pt bi-layer grown on a glass substrate, simultaneously exerting spin-transfer torques through the spin-Hall effect and also causing Joule heating enabling the control of the device temperature. We measured the device temperature by using the device itself as a local temperature sensor. A clear reduction of CoFeB magnetisation was observed as the device temperature was increased allowing us to estimate the Curie temperature of our CoFeB film to be 920 K. The spin-Hall angle of Pt was quantified as (1.72 ± 0.03) × 10⁻² at 300 K and was slightly increased to (1.75 ± 0.02) × 10⁻² at 410 K. This simple method can be widely used for quantifying the spin-Hall angle of a large variety of materials at high temperatures.

DOI： 10.1016/j.jmmm.2019.04.070

Language：English   Publishing type：Research paper (scientific journal)  

Inducing oxygen vacancy defects in SrTiO₃ powders via high temperature treatment in the presence of a mixture of Ar, O₂, dry air, and H₂ ambient gases is a promising strategy to produce homogeneously defective SrTiO₃ photocatalysts with a remarkable 40-fold enhancement of H₂ evolution activity. Electron doping of SrTiO₃ due to oxygen vacancies triggers the development of a highly active SrTiO₃ photocatalyst; however, the photodynamic processes involved in these modifications of SrTiO₃ have not been fully elucidated yet. In this work, we investigated the impact of high temperature treatment based on the dynamics of photocarriers by transient absorption spectroscopy (TAS). TAS results revealed that upon band gap excitation of SrTiO₃, most of the photoexcited electrons in non-reduced SrTiO₃ are deeply trapped in the intrinsic defects as evident from the strong broad absorption signals peaking at 11 000 cm^-1 (909 nm, 1.36 eV) and 20 000 cm^-1 (500 nm, 2.48 eV), whereas the absorption intensities in this wavenumber region largely decreased in highly reduced SrTiO₃, suggesting a possible electron filling of deeply trapped states via reduction treatment (or electron doping). Interestingly, the photoexcited electrons in oxygen-deficient SrTiO₃ preferably occupy the shallower electron traps. The lowest energy limit of the electron trap filled by photoexcited electrons is estimated to be at the absorption edge located at 1000 cm^-1 (∼0.12 eV below the conduction band), which is much shallower than that of non-reduced SrTiO₃ (>0.7 eV). Furthermore, it was found that the electron population in the shallow traps in highly reduced SrTiO₃ is nearly 2 orders of magnitude higher compared to that in non-reduced SrTiO₃, indicating a large improvement in the electron lifetime. The findings herein offer significant insights into the crucial impact of the reduction of SrTiO₃via induced oxygen vacancy defects to provide available photoexcited electrons that can be readily utilized for the H₂ generation reaction.

DOI： 10.1039/c9ta08216f

Language：English   Publishing type：Research paper (scientific journal)  

Two-step, solar-driven thermochemical fuel production offers the potential of efficient conversion of solar energy into dispatchable chemical fuel. Success relies on the availability of materials that readily undergo redox reactions in response to changes in environmental conditions. Those with a low enthalpy of reduction can typically be reduced at moderate temperatures, important for practical operation. However, easy reducibility has often been accompanied by surprisingly poor fuel production kinetics. Using the La1-xSr xMnO3 series of perovskites as an example, we show that poor fuel production rates are a direct consequence of the diminished enthalpy. Thus, material development efforts will need to balance the countering thermodynamic influences of reduction enthalpy on fuel production capacity and fuel production rate.

DOI： 10.1557/mrc.2017.108

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

The influence of NiO, used as a sintering aid, on the transport properties of BaZr_0.8Y_0.2O_{3 - Δ} was investigated by monitoring electrical conductivity relaxation of specimens with and without NiO during hydration in atmospheres of different oxygen activities at 700 and 800 °C. The chemical diffusivities of H and O governing the kinetics were precisely evaluated from the transient conductivity, and all the defect-chemical parameters - the two external equilibrium constants and mobilities of all the carriers, V_O^{· ·}, H_i^· and h^· - were determined from the steady-state equilibrium conductivity. It is found that the processing benefits afforded by NiO are accompanied by a significant reduction in ionic mobilities and hydration reaction constant. These factors, in turn, result in a smaller electrolytic regime in the presence of NiO than when it is absent.

DOI： 10.1016/j.ssi.2015.01.001

Language：English   Publishing type：Research paper (scientific journal)  

We demonstrate that solid-state NMR spectra of challenging nuclei with a low gyromagnetic ratio such as yttrium-89 can be acquired quickly with indirect dynamic nuclear polarization (DNP) methods. Proton to ⁸⁹Y cross polarization (CP) magic angle spinning (MAS) spectra of Y³⁺ in a frozen aqueous solution were acquired in minutes using the AMUPol biradical as a polarizing agent. Subsequently, the detection of the ⁸⁹Y and ¹H NMR signals from technologically important hydrated yttrium-doped zirconate ceramics, in combination with DFT calculations, allows the local yttrium and proton environments present in these protonic conductors to be detected and assigned to different hydrogen-bonded environments.

DOI： 10.1021/jz5007669

Language：English   Publishing type：Research paper (scientific journal)  

A review of the experimental literature documenting water uptake in yttrium-doped barium zirconate in combination with new results obtained here show that much of the observed scatter can be explained in terms of barium deficiency, which furthermore induces a lowering in cell volume. In addition, through a comparison of weight changes under regular and heavy water vapor pressure, strong evidence is found for bulk oxidation of the oxide by water simultaneous with hydration.

DOI： 10.1016/j.scriptamat.2010.12.034

Language：English   Publishing type：Research paper (scientific journal)  

Tracer diffusion coefficients of ⁶⁷Cu and ⁶⁴Cu in CVD β-Silicon carbide (β-SiC) have been measured in the temperature range between 623 and 1373 K by use of a serial ion-beam sputter-microsectioning technique. The temperature dependence of the diffusion coefficient D is expressed by D_Cu^* = 8 . 2_{- 0.5}^{+ 0.5} × 1 0^{- 16} exp (- 41 ± 1 kJ mol^{- 1} / RT) m² s^{- 1} . The diffusion coefficient of Cu in β-SiC is larger than those of Si and C by more than six orders of magnitude and those of Fe and Cr by one-three orders of magnitude. The activation energy for the diffusion of Cu is about one twentieth of that for the self-diffusion. The results suggest that an interstitial mechanism operates on the diffusion of Cu in β-SiC.

DOI： 10.1016/j.jpcs.2007.07.007

Language：English   Publishing type：Research paper (scientific journal)  

Tracer diffusion coefficient of 181W in -iron has been determined in the temperature range between 833 and 1173 K using a serial sputter-microsectioning method. The temperature dependence of the diffusion coefficient, D, over the whole temperature range of -iron across the Curie temperature (TC = 1043 K), can be expressed by [image omitted] where s is the ratio of the spontaneous magnetization at T K to that at 0 K. The factor 0.086 in the above equation is smaller than 0.156 for the self-diffusion, showing that the influence of the magnetic transformation on the diffusion of tungsten in -iron is smaller than that on the self-diffusion. The activation energy 287 kJ/mol for tungsten diffusion in the paramagnetic iron is much higher than 250.6 kJ/mol for the self-diffusion. Atomic size effect is predominant in the activation energies for diffusion of transition elements in the paramagnetic -iron.

DOI： 10.1080/14786430600732093

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

The diffusion coefficient of ⁹⁵Nb in pure Nb and Nb-H alloys whose hydrogen concentration ranges between H/Nb = 0.05 and 0.34 in atomic ratio has been determined in the temperature range 823-1598 K using a serial sputter-microsectioning technique. The diffusion coefficient of Nb in the Nb-H alloys was found to increase significantly with increasing hydrogen concentration. The dependence of the diffusion enhancement on temperature and hydrogen concentration was examined in some detail, and explained tentatively in terms of average occupation number of hydrogen atoms per vacancy, r. The diffusion enhancement comes primarily from the decrease of the activation energy Q, resulting from the increase of r with increase of hydrogen concentration. Some remaining problems with this interpretation are pointed out for future investigations.

DOI： 10.1016/j.actamat.2005.02.049

Language：English   Publishing type：Research paper (scientific journal)  

Interdiffusion between metals of widely different diffusional characteristic is interesting in view of the fact that several anomalous features appear during interdiffusion owing to the large difference between the fluxes of the diffusing species. In some binary systems, it has been observed that the interdiffusion coefficients determined by multi-phase couples are smaller than those determined through the single-phase couples. This observation implies that the Boltzmann-Matano analysis is unapplicable to such cases. In the present article, this phenomenon is reviewed in the Au-Fe and Au-Ni systems, which have large differences in the diffusivities between the components. Recent experimental results on diffusion enhanced by vacancies induced under elevated hydrogen pressure are helpful to resolve the problems.

DOI： 10.4028/www.scientific.net/ddf.237-240.62

Language：English   Publishing type：Research paper (scientific journal)  

Experimental techniques for precise determination of low tracer diffusion coefficients in solid metals and alloys using radioisotopes are reviewed. Sputter-microsectioning method is most useful to measure submicron diffusion profiles at low temperatures. Measurements of tracer diffusivity along grain boundaries and dislocations in iron and stainless steels from the analysis of type C kinetics as well as type B kinetics are discussed.

DOI： 10.2320/jinstmet.69.321

Language：English   Publishing type：Research paper (scientific journal)  

Self-diffusion coefficient of ⁹⁵Nb in NbH_x alloys (x=0.05, 0.25 and 0.3) has been determined in the temperature range from 823 to 1323 K by using a serial sputter-microsectioning technique. The self-diffusion coefficient of Nb in the NbH_x alloys are larger than that in Nb, suggesting that vacancies are formed by hydrogen dissolution, that is, the formation of hydrogen-induced vacancies. The value of the pre-exponential factor for the Nb diffusion in the NbH_0.05 alloy is five times larger than that in Nb, while the difference in the activation energies between the NbH _0.05 alloy and pure Nb is small. The self-diffusion enhancement in the NbH_0.05 alloy is mainly caused by lowering in vibrational frequencies of atoms in the immediate neighborhood of hydrogen-induced vacancies.

Language：English   Publishing type：Research paper (scientific journal)  

Grain boundary diffusivity of chromium in SUS316 and 316L stainless steels has been determined in the temperature range between 518 and 1173 K. The magnitudes of the grain boundary diffusivities in four kinds of specimens are in the order of the cold-worked SUS316, the solution-treated SUS316L, the solution-treated SUS316 and the sensitized SUS316. The grain boundary diffusivities in these specimens are remarkably higher than those of previous works. The activation energies for the former are 85-91 kJmol^-1, whereas those for the latter are 151-234 kJmol^-1.

DOI： 10.2320/matertrans.45.2945

Language：English   Publishing type：Research paper (scientific journal)  

Grain boundary diffusivities of ⁵⁹Fe and ⁵⁷Co in a binary Fe-50 at.%Co alloy have been determined at a temperature range between 883 and 1123 K by serial sputter-microsectioning technique using specimen unidirectionally solidified at three different solidification rates of 12000, 60 and 32 mm/h. Above the order-disorder transformation temperature of 1003 K, the Arrhenius plots of the grain boundary diffusivities in the alloy solidified at three rates show straight lines. The diffusivities in the specimen with 32 mm/h are higher than those with 60 and 12000 mm/h. Below 1003 K, all the Arrhenius plots of the diffusivities show downward curvature remarkably owing to the atomic ordering. From the analysis of depth profiles, the atomic ordering gives large influence on the diffusion along subgrain boundaries rather than the diffusion along random grain boundaries.

DOI： 10.1016/j.msea.2004.05.056

Language：English   Publishing type：Research paper (scientific journal)  

The self-diffusion coefficients D_Fe and D_Co of radioactive tracers ⁵⁹Fe and ⁵⁷Co, respectively, in a binary Fe-50 at.% Co alloy were experimentally determined for the disordered (α) phase with the body-centered cubic (bcc) structure and the ordered (α′) phase with the B2 structure using specimens solidified unidirectionally at solidification rates of 32, 60 and 12,000 mm/h. These specimens were electroplated with the tracers and then heat treated at a temperature range between 883 and 1123 K for various times of 1.5 × 10³-1.204 × 10⁶ s. Penetration profiles of the tracers in the heat treated specimen were measured by a serial sputter-microsectioning technique. The measurement implies that the penetration of each tracer is controlled by the volume diffusion. As to the α phase, the values of D_Fe and D _Co coincide well with those obtained by lijima and Lee using well annealed polycrystalline specimens of a binary Fe-50 at.% Co alloy. On the other hand, D _Fe and D _Co in the α′ phase are greater for the unidirectionally solidified specimen than for the well-annealed polycrystalline specimen. Such greater values of D _Fe and D _Co are attributed to the contribution of the dislocation diffusion.

DOI： 10.1016/j.msea.2004.05.055

Language：English   Publishing type：Research paper (scientific journal)  

The diffusion coefficient D_Fe* of Fe in Au under a H ₂ pressure of 5GPa has been determined in the temperature range from 1004 to 1301K by relating the interdiffusion coefficients in single-phase Au-(Au-Fe) couples with the Darken-Manning relation. The value of D _Fe*, in Au at 130IK under a H₂2 pressure of 5 GPa is three times that under a pressure of 5 GPa without H₂, whereas the former is one tenth of that under a He pressure of 0.1 MPa. The temperature dependence of D_Fe* in Au under a H₂ pressure of 5 GPa can be expressed as D_Fe* = 7.8_-5.6 ⁺²⁰ × 10^-6 exp(-195 ± 12 kJ mol ^-1/RT) m² s^-1. The pre-exponential factor is nearly equal to that in He at 0.1 MPa, although the activation energy is only 21 kJ mol^-1 larger than that observed in He at 0.1 MPa. This behaviour contrasts with that in γ-Fe, which has a very high solubility of H₂ under high pressures.

DOI： 10.1080/09500830310001655202

Language：English   Publishing type：Research paper (scientific journal)  

The diffusion coefficients of Au, D_Au*, in γ-Fe in the temperature range from 1263 to 1653 K at 0.1 MPa Ar and from 1207 to 1351 K at 3-5 GPa H₂ have been determined by relating the interdiffusion coefficients in single-phase Fe/Fe-Au couples with the Darken-Manning relation. The value of D_Au* in γ-Fe at 5 GPa H₂ is 2-3 times larger than that at 0.1 MPa Ar. The temperature dependence of D _Au* in γ-Fe at 0.1 MPa Ar and at 5 GPa H₂ can be expressed as D_Au*=8.1_-2.3 ^+3.2×10^-5exp{-(290±4)kJmol^-1/RT} m² s^-1 and D_Au*=1.4×10 ^-3exp(-310kJmol^-1/RT) m² s^-1, respectively. The value of the activation energy at 5 GPa H₂ is 20 kJ mol^-1 larger than that at 0.1 MPa Ar, whereas the value of the pre-exponential factor at 5 GPa H₂ is 17 times larger than that at 0.1 MPa Ar. Therefore, the enhancement of the diffusion at 5 GPa H₂ is attributed to a high value of activation entropy.

DOI： 10.1016/j.actamat.2003.11.008

Language：English   Publishing type：Research paper (scientific journal)  

Japan. Diffusion in a metal under an elevated hydrogen pressure is interesting in view of the fact that the diffusion is enhanced owing to the injection of a large amount of vacancies into the metal. This is peculiar to an elevated hydrogen pressure because diffusion in a metal is generally suppressed under a hydrostatic pressure. In the present article, the effect of an elevated hydrogen pressure on interdiffusion and impurity diffusion is reviewed in the Au-Fe system which has a large difference in the hydrogen solubilities between γ -Fe and Au under an elevated hydrogen pressure.

DOI： 10.4028/www.scientific.net/ddf.233-234.115

Language：English   Publishing type：Research paper (scientific journal)  

Diffusion behavior of Cd in volume and along dislocations in high-purity CdTe annealed in Te-saturated atmosphere has been studied by the radioactive tracer method with a serial ion-beam sputter-microsectioning technique. The temperature dependence of volume diffusion coefficients shows a bend around 773K, whereas that of the self-diffusion along dislocations shows a straight line. This suggests that the defect induced by impurities enhances the volume diffusion but does not affect the diffusion along dislocations.

DOI： 10.1016/j.mssp.2003.07.020

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The hydriding and dehydriding behavior of LaNi_5-xCo_x (0≤x≤2) was studied by the pressure differential scanning calorimetry (PDSC) at the hydrogen pressure range of 1-5 MPa in the temperature range from 323 to 573 K. In the heating run of the LaNi₅-H₂ system, two endothermic peaks were observed. One was the peak for the transformation from the γ phase (LaNi₅H₆ hydride) to the β phase (LaNi₅H₃ hydride). The other was the peak for the transformation from the β phase to the α phase (solid solution). In the cooling run, one exothermic peak for the transformation from the α phase to the γ phase was observed. In the range of x≤0.5, PDSC curves similar to that of the LaNi₅-H₂ system were observed. However, in the range of x≥1, one endothermic and one exothermic peaks were observed in the heating and cooling runs, respectively. Using Ozawa's method, the activation energies for the dehydriding processes were estimated. The activation energy for the γ-β transformation was higher than that for the β-α transformation and the activation energy for the β-α transformation has a maximum at the composition of about x = 1.

DOI： 10.1016/S0966-9795(03)00103-1

Language：English   Publishing type：Research paper (scientific journal)  

Interdiffusion coefficient in the B2 FeAl phase at 46-50 at%Al has been measured in the temperature range from 1173 to 1473 K under the pressure from 0.1 MPa to 5 GPa. The activation volume for interdiffusion, ΔV̄, derived from the pressure dependence of interdiffusion coefficient is found to be 0.58-0.90V_m (V_m: molar volume of alloys), which is comparable to or larger than 0.4-0.6V_m for the monovacancy mechanism in bcc pure metals or random alloys. The value of ΔV̄ increases with increasing temperature and also with deviating from stoichiometry, suggesting that divacancy contributes to the diffusion in higher temperatures and in the region of off-stoichiometry.

DOI： 10.2320/matertrans.44.78

Language：English   Publishing type：Research paper (scientific journal)  

Tracer diffusion coefficient of molybdenum in α-iron was determined in the temperature range between 833 and 1163 K by using a serial sputter-microsectioning technique. The temperature dependence of the diffusion coefficient, D, in the whole temperature range of α-iron across the Curie temperature was found out. Results showed that the influence of the magnetic transformation on the diffusion of molybdenum in α-iron was smaller than that on the self-diffusion as expected from the negative magnetic moment of molybdenum.

DOI： 10.1016/S1359-6454(02)00229-X

Language：English   Publishing type：Research paper (scientific journal)  

The hydrogenation and dehydrogenation behavior of LaNi₅, LaNi_4.75 Co_0.25 and LaNi₃Co₂ was studied by the pressure differential scanning calorimetry (PDSC) at the hydrogen pressure range of 1 to 5 MPa in the temperature range from 323 to 473 K with the heating and cooling rates of 2 to 30 K min^-1. In the heating run of the hydride of LaNi₅, two endothermic peaks were observed. One was the peak for the transformation from the γ phase (full hydride LaNi₅H₆) to the β phase (hydride LaNi₅H₃). The other was the peak for the transformation from the β phase to the α phase (solid solution). In the cooling run, one exothermic peak for the transformation from the α phase to the γ phase was observed. These endothermic and exothermic peaks shifted to higher temperatures with the increase in hydrogen pressure. In the heating and cooling runs of the LaNi_4.75Co_0.25-H₂ system the PDSC curves similar to those of the LaNi₅-H₂ system were observed. However, in the heating run of the hydride of LaNi₃Co₂ only one endothermic peak was observed. Using Ozawa's method, the activation energies for dehydrogenation of the hydrides were estimated. The activation energy for the γ-β transformation was higher than that for the β-α transformation. Substitution of cobalt for a part of nickel in LaNi₅ increased the activation energies for the phase transformations.

DOI： 10.2320/matertrans.43.1095

Language：English   Publishing type：Research paper (scientific journal)  

Nitrogen and hydrogen absorptions have been carried out in order to discuss the influence of interstitial atoms on the magnetovolume effects for the La(Fe _xAl _1-x) ₁₃ (x=0.83 and 0.86) compounds. The average magnetic hyperfine field and the Curie temperature T _C of nitrides are lower than that of hydrides. The volume expansion due to the nitrogen absorption is about twice that due to the hydrogen absorption. Comparing the change in T _C of the nitrides with that of hydrides and the pressure effect on T _C, the hybridization between the Fe 3d and N 2p orbital should be taken into consideration in the lower T _C of nitrides.

DOI： 10.1063/1.1452711

Language：English   Publishing type：Research paper (scientific journal)  

Interdiffusion coefficients, D̃, in the B2 type NiAl, CoAl and FeAl phases have been determined by single phase diffusion couples over a wide temperature range from 1073 to 1773 K. The value of D̃ in the NiAl and CoAl phases shows a minimum at about 47 at.% Al deviating slightly from the stoichiometric composition, while the value of D̃ in the FeAl phase has a weak minimum at about 41 at.% Al. The value of the activation energy, Q̃, for interdiffusion in the NiAl and CoAl phases shows a maximum at about 47 at.% Al, where the value of Q̃ in the CoAl phase is much higher than that in the NiAl phase, while the value of Q̃ in the FeAl phase is nearly constant and much lower than those in the other two phases. It is observed that the larger the lattice constant of the compounds becomes, the lower the activation energy for diffusion in the compounds becomes. Thus, the magnitude of activation energy for diffusion in the B2 type NiAl, CoAl and FeAl is probably related to the lattice constant of the compounds. Using the interdiffusion coefficient and the tracer diffusion coefficients of Ni and Fe with the help of Darken's relation, the diffusion coefficient of Al in the NiAl and FeAl phases has been estimated.

DOI： 10.1016/S0966-9795(01)00125-X

Language：English   Publishing type：Research paper (scientific journal)  

Self-diffusion along dislocations in ultra high purity iron containing 0.5-1.2 mass ppm carbon, 0.1-1.0 mass ppm nitrogen and 1.8-4.0 mass ppm oxygen has been studied by the radioactive tracer method with the sputter-microsectioning technique. Below 700 K, the self-diffusion coefficient along dislocations has been determined directly from the type C kinetics classified by Harrison, whereas above 800 K it has been obtained by the type B kinetics assuming that the effective radius of dislocation pipe is equal to 5 × 10^-10 m. The temperature dependence of the self-diffusion coefficient along dislocations does not show a linear Arrhenius relation. Below 900 K the Arrhenius plot shows slightly downward curvature. However, above 900 K the self-diffusion coefficient along dislocations increases remarkably with increasing temperature. The value at 900 K is 10^-14 m²s^-1, while it takes 10^-10 m²s^-1 at the Curie temperature (1043 K). It seems that the steep increase of the self-diffusion coefficient along dislocations near the Curie temperature is related to the magnetic transformation in ultra high purity iron.

DOI： 10.2320/matertrans.43.173

Language：English   Publishing type：Research paper (scientific journal)  

Volume and grain boundary diffusivities of ⁵¹Cr and ⁵⁹Fe in a high purity Fe-50 mass% Cr-8 mass% W (Fe-50Cr-8W) alloy have been determined in the temperature range between 1023 and 1373 K with the sputter-microsectioning technique. The volume diffusion coefficients of Cr and Fe in the Fe-50Cr-8W alloy are smaller than those in a high-purity Fe-50 mass% Cr (Fe-50Cr) alloy. Linear Arrhenius lines for the volume self-diffusion coefficients of both tracers have been observed in the temperature range examined. The activation energies for the volume diffusion of both components in the Fe-50Cr-8W alloy are somewhat smaller than those in the Fe-50Cr alloy. On the other hand, the grain boundary diffusivities of Cr and Fe in the Fe-50Cr-8W alloy at 1123 K are about two orders of magnitude smaller than those in the Fe-50Cr alloy.

DOI： 10.2320/matertrans.43.178

Language：English  

Language：English   Publishing type：Research paper (scientific journal)  

A magnetic entropy change ΔS_M due to the itinerant-electron metamagnetic (IEM) transition was estimated to be -23 J/kg K around the Curie temperature for La(Fe_0.88Si_0.12)₁₃ in the magnetic field change from 0 to 5 T. In order to control the Curie temperature while keeping such a large value of ΔS_M, hydrogen absorption was carried out. La(Fe_0.88Si_0.12)₁₃H_1.0 with T_C = 274 K shows a large ΔS_M due to the IEM transition around room temperature. The adiabatic temperature change ΔT_ad from 0 to 2 T is about 7 K, comparable to that of Gd₅(Ge_0.5Si_0.5)₄. By changing the hydrogen concentration, the Curie temperature can be controlled from 195 to 336 K. It should be noted that the magnitude of ΔS_M is almost the same after hydrogen absorption. Therefore, the hydrogenated La(Fe_0.88Si_0.12)₁₃H_y compounds are promising magnetic refrigerants working in a wide range of temperature.

DOI： 10.2320/matertrans.43.1202

Language：English   Publishing type：Research paper (scientific journal)  

The Bundesanstalt für Materialforschung und -prüfung (Federal Institute for Materials Research and Testing) (BAM) is establishing a system of primary reference materials to meet the demands for metrological traceability and to act as national standards in the field of elemental analysis. For all elements of the periodic table - except those that are gases or radioactive - two different kinds of reference materials are being certified. One is for analyte calibration (Type A) and one for problems concerning matrix matching (Type B). These substances are of very high purity and of defined stoichiometry. As far as possible, pure elements and metals rather than pure compounds are used. The certification of both types of material requires most elements of the periodic table to be certified at very low levels using trace element analysis methods. The application of these methods is described and examples of the certification of copper and iron are given.

DOI： 10.1002/1521-396X(200201)189:1<107::AID-PSSA107>3.0.CO;2-1

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

La(Fe_xSi_1-x)₁₃ compounds exhibit an itinerant-electron metamagnetic (IEM) transition above Curie temperature T_C. The IEM transition in the compound with x=0.88 is accompanied by a giant volume change. From a practical viewpoint, T_C was controlled by hydrogen absorption in order to obtain such a giant volume magnetostriction at room temperature. For the La(Fe_0.88Si_0.12)₁₃H_1.0 compound, the IEM transition occurs above T_C = 278 K, and a significant isotropic linear magnetostriction of about 0.3% at 7 T is induced in the vicinity of room temperature. This large magnetostriction is attributed to the giant volume magnetostriction of about 1% by the IEM transition.

DOI： 10.1063/1.1388157

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

Impurity tracer diffusion of ⁵⁹Fe, ⁵¹Cr and ⁵⁷Co in CVD β-SiC has been studied in the temperature range between 973 and 1873 K. The temperature dependence of the volume diffusion coefficients of iron and chromium can be expressed by linear Arrhenius equations. The preexponential factor and the activation energy are estimated to be 8.7 × 10^-15 m² s^-1 and 111 kJ mol^-1 for iron, respectively, and 9.5 × 10^-15 m² s^-1 and 81 kJ mol^-1 for chromium, respectively. The diffusion coefficients of iron and chromium are much higher than those of the self-diffusion in β-SiC. Furthermore, the activation energies for the diffusion of iron and chromium are about one-tenth of those for carbon and silicon in β-SiC. Therefore, it seems that an interstitial mechanism is predominant for the diffusion of iron and chromium in β-SiC. On the other hand, the diffusion coefficient of cobalt above 1673 K is higher than that of iron, while at lower temperatures it is much lower than that of iron. The difference in the diffusion coefficients at 1173 K is more than three orders of magnitude. Thus, the temperature dependence of the diffusion coefficients of cobalt shows a strongly curved Arrhenius relation. This suggests that cobalt atoms diffuse by an interstitial mechanism at higher temperatures and by a substitutional mechanism at lower temperatures. From the deeper regions of the penetration profiles of iron, chromium and cobalt the dislocation diffusion coefficients of them have been estimated.

DOI： 10.1016/S1468-6996(01)00015-8

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

Impurity diffusion of Al and Cu in γ-Fe has been studied by using non-radioactive tracer elements. Penetration profiles have been determined by the lathe sectioning and the instrumental analyses, namely, absorptiometry for Al and atomic absorption analysis for Cu. Penetration curves obtained have been good for the diffusion analysis. The absorptiometry and atomic absorption analysis are found to be useful to measure the penetration profile for the impurity diffusion in metals where suitable radioisotope as a tracer is unavailable or the half-life of radioisotope is very short.

DOI： 10.4028/www.scientific.net/ddf.194-199.91

Language：English  

Language：English  

Language：English   Publishing type：Research paper (scientific journal)  

The change in magnetic properties of La(Fe_0.88 Al_0.12)₁₃ by hydrogenation has been investigated. The NaZn₁₃-type structure is preserved and the lattice constant is increased after hydrogenation, showing that the hydrogen atoms intrude into the position between the icosahedral clusters and La atoms. By hydrogenation, the magnetic ground state is changed from the antiferromagnetic to the ferromagnetic state, accompanied by significant increases in the spontaneous magnetic moment and the Curie temperature.

DOI： 10.1016/S0925-8388(00)01468-7

Language：English   Publishing type：Research paper (scientific journal)  

The interdiffusion coefficients D̃ in the Au/γ-Fe two-phase and the Au/Au-37at%Fe single-phase couples have been determined under the hydrostatic pressure (HP) and hydrostatic hydrogen pressure (HHP) of 5 GPa at 1263 K. The value of D̃ in the Au-rich phase of the Au/γ-Fe couple under the HHP of 5 GPa is 4 times larger than that under the HP of 5 GPa, while the value of D̃ in the γ-Fe phase under the HHP is 50 times larger than that under the HP, implying that the concentration of vacancies injected by the HHP into the γ-Fe phase is much larger than that into the Au-rich phase. The enhancement of the interdiffusion in the Au/γ-Fe couple by the HHP of 5 GPa is attributed to the enlargement of vacancy flow from the γ-Fe phase towards the Au-rich phase in the couple.

DOI： 10.4028/www.scientific.net/ddf.194-199.1069

Language：English  

Language：English   Publishing type：Research paper (scientific journal)  

Diffusion of protium in the α phase (solid solution), the ά phase (α phase dehydrided from the β phase) and the β phase (hydride) of LaNi₅-H alloys was studied by the desorption method. It was observed that the diffusion coefficient of protium in the β phase was a little higher than that in the α phase and that these were much higher than that in the ά phase. The difference between the diffusion coefficients in the three phases is attributed to the difference in the protium concentration between the α phase and the β phase and to the difference in the trapping density between the α phase and the ά phase.

DOI： 10.2320/jinstmet1952.65.9_803

Language：English   Publishing type：Research paper (scientific journal)  

The growth kinetics of the intermetallic compounds and of the β-Ti phase in the diffusion couples composed of Au and α-Ti were investigated in the narrow temperature range between the eutectoid temperature (α-Ti, β-Ti and AuTi₃ ) and the temperature of the α-β allotropic transformation of Ti. Four intermetallic compounds, Au₄Ti, Au₂Ti, AuTi and AuTi₃, predicted from the Au-Ti phase diagram have been observed in the diffusion zone. The Au₂Ti and AuTi₃ phases are not the stoichiometric compounds but have a narrow concentration range of about 1 at%. The layer growth of the four intermetallic compounds and the β-Ti phase obeys a parabolic law, namely the value of time exponent of layer growth is nearly equal to 1/2. The layer growth of the β-Ti phase is much faster than that of intermetallic phases. The Arrhenius relation of the growth rate constants of these layers have been observed. The activation energies for the layer growth of intermetallic compounds are found to be extremely high.

DOI： 10.4028/www.scientific.net/ddf.194-199.1569

Language：English   Publishing type：Research paper (scientific journal)  

Tracer self-diffusion coefficients of ⁵¹Cr and ⁵⁹Fe in a high purity Fe-50 mass%Cr alloy have been determined in the temperature range between 923 and 1273 K by use of the sputter-microsectioning technique. A linear Arrhenius line has been observed for each self-diffusion across the α-σ phase transformation temperature 1103 K, which is consistent with the suppression of the σ phase formation by purification. The Arrhenius equations can be expressed by D_Cr = 0.54 × 10^-4 exp(-251 kJ mol^-1/RT)m² s^-1 and D_Fe = 0.30 × 10^-4 exp(-243 kJ mol^-1/RT) m² s^-1. The activation energies for the self-diffusion of Cr and Fe by the present work are much lower than 293 and 312 kJ mol^-1 determined previously by Paxton et al. in the temperature range from 1223 to 1523 K, respectively.

DOI： 10.2320/matertrans1989.41.87

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

The magnetic properties of Sm-Co-Cu films and Sm-Co-Cu/Co multilayered films prepared by rf-sputtering were investigated. The addition of Cu to Sm-Co film had the effect of decrement of crystallization temperature. The Sm₂₈Co₃₉Cu₁₃ film annealed for 1 h at 623 K showed a reversible demagnetization curve with 82% springback ratio of [Mr' -M(H)]/[Mr-M(H)] and a high coercivity of 2480 kA·m^-1. This film was found to be an exchange-spring magnet film composed of the hard magnetic phase such as SmCo₅ and Sm₂Co₇ phases and a soft magnetic phase of Co. Sm₂₈Co₅₉Cu₁₃/Co(x nm) multilayered film whose Co thickness was from 0 to 15 nm was also found to be an exchangespring magnet film.

DOI： 10.2320/matertrans1989.39.302

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

The structure and magnetic properties of Sm-Co films and Sm-Co/M (M=Co, Fe) multilayered films prepared by rf sputtering were investigated. The results show that a hard magnetic phase as Sm₂Co₁₇ and SmCo₅ phase and a soft magnetic phase were formed by annealing Sm-Co and Sm-Co/M films. Sm₁₆Co₈₄ film annealed for 1.8 ks at 773 K had the springback ratio of [Mr′-M(H)]/[Mr-M(H)]=0.72. This film was found to behave as a exchange-spring magnet composed of a hard magnetic phase and a soft magnetic phase. Sm₁₆Co₈₄/Fe multilayered film was also found to be a exchange-spring magnet.

DOI： 10.2497/jjspm.44.827

Event date： 2023.11

Language：Japanese  

Venue：北海道大学   Country：Japan  

Event date： 2023.6

Language：English  

Country：Greece  

Event date： 2023.5

Language：Japanese  

Venue：グローカルホテル糸島　福岡   Country：Japan  

Event date： 2023.4 - 2024.4

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：TKP東京駅カンファレンスセンター   Country：Japan  

Event date： 2023.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：仙台   Country：Japan  

Event date： 2023.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：仙台   Country：Japan  

Event date： 2023.3

Language：Japanese  

Venue：東北工業大学八木山キャンパス   Country：Japan  

Event date： 2022.12

Language：English   Presentation type：Oral presentation (general)  

Venue：Boston   Country：United States  

Event date： 2022.12

Language：English   Presentation type：Oral presentation (general)  

Venue：仙台   Country：Japan  

Event date： 2022.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：仙台   Country：Japan  

Event date： 2022.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：仙台   Country：Japan  

Event date： 2022.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：仙台   Country：Japan  

Event date： 2022.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：横浜   Country：Japan  

Event date： 2022.11

Language：English   Presentation type：Oral presentation (general)  

Venue：Phu Quoc   Country：Viet Nam  

Event date： 2022.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Event date： 2022.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Event date： 2022.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Event date： 2022.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Event date： 2022.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：徳島   Country：Japan  

Event date： 2022.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：徳島   Country：Japan  

Event date： 2022.8

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Fukuoka   Country：Japan  

Event date： 2022.6

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：北九州   Country：Japan  

Event date： 2022.6

Language：English   Presentation type：Oral presentation (general)  

Venue：北九州   Country：Japan  

Event date： 2022.6

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：北九州   Country：Japan  

Event date： 2022.5

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Event date： 2022.3

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Venue：オンライン   Country：Japan  

Event date： 2022.3

Language：Japanese  

Country：Japan  

Event date： 2021.12

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2021.12

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2021.9 - 2021.10

Language：English  

Venue：オンライン   Country：Germany  

Event date： 2021.9 - 2021.10

Language：English  

Venue：オンライン   Country：Germany  

Event date： 2021.9

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2021.9

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2021.9

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2021.9

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2021.7

Language：Japanese  

Country：Japan  

Event date： 2021.6

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2021.6

Language：Japanese  

Country：Japan  

Event date： 2021.6

Language：English  

Venue：オンライン   Country：Japan  

Event date： 2021.1

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Venue：オンライン   Country：Japan  

Event date： 2020.12

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2020.12

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2020.12

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2020.12

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2020.6

Language：Japanese  

Country：Japan  

Event date： 2020.6

Language：English   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2020.1

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学   Country：Japan  

Event date： 2020.1

Language：Japanese  

Venue：九州大学   Country：Japan  

Event date： 2020.1

Language：Japanese  

Venue：九州大学   Country：Japan  

Event date： 2020.1

Language：Japanese  

Venue：九州大学   Country：Japan  

Event date： 2020.1

Language：Japanese  

Venue：九州大学   Country：Japan  

Event date： 2020.1

Language：Japanese  

Venue：九州大学   Country：Japan  

Event date： 2019.12

Language：English   Presentation type：Oral presentation (general)  

Venue：横浜シンポジア   Country：Japan  

Event date： 2019.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：かんぽの宿　奈良   Country：Japan  

Event date： 2019.10 - 2019.11

Language：English   Presentation type：Symposium, workshop panel (public)  

Venue：沖縄コンベンションセンター   Country：Japan  

Event date： 2019.10 - 2019.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：沖縄コンベンションセンター   Country：Japan  

Event date： 2019.10 - 2019.11

Language：English   Presentation type：Symposium, workshop panel (public)  

Venue：沖縄コンベンションセンター   Country：Japan  

Event date： 2019.10

Language：English   Presentation type：Symposium, workshop panel (public)  

Venue：Sommarøy Arctic Hotel Tromsø   Country：Norway  

Event date： 2019.10

Language：English   Presentation type：Symposium, workshop panel (public)  

Venue：九州大学   Country：Japan  

Event date： 2019.9

Language：English   Presentation type：Oral presentation (general)  

Venue：岡山大学   Country：Japan  

Event date： 2019.9

Language：Japanese  

Venue：ノースウエスタン大学   Country：United States  

Event date： 2019.9

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Venue：湖邸滋びわこクラブ   Country：Japan  

Event date： 2019.7

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Venue：北九州国際会議場   Country：Japan  

Event date： 2019.7

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Venue：北九州国際会議場   Country：Japan  

Event date： 2019.7

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Venue：北九州国際会議場   Country：Japan  

Event date： 2019.7

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Venue：北九州国際会議場   Country：Japan  

Event date： 2019.7

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Venue：北九州国際会議場   Country：Japan  

Event date： 2019.7

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Venue：北九州国際会議場   Country：Japan  

Event date： 2019.6

Language：English   Presentation type：Oral presentation (general)  

Venue：TITANIA HOTEL（Athens）   Country：Greece  

Yttrium-doped barium zirconate shows high proton diffusivity at an intermediate temperature. Such feature is beneficial as an electrolyte for solid oxide fuel cells operated at the temperatures. Though high, the proton diffusion is hindered by trapping effect. It is an attractive interaction with relatively negatively charged dopant that reduces the fraction of mobile protons (H+), more severely at lower temperatures [1]. The effect was experimentally confirmed by electrochemical measurement combined with thermogravimetry as well as high-temperature proton NMR. The 20at% Y-doped barium zirconate sample contained about 0.05 protons and 0.075 oxygen vacancies per formula unit. Now, there is a discussion in which the existing oxygen vacancies might have an impact on the proton trapping. To investigate it, we prepared fully hydrated pellet, BaZr0.8Y0.2O2.9H0.2, that does not contain any oxygen vacancies and performed electrochemical measurements. Proton diffusivities in the partially and fully hydrated pellets are almost equivalent, both indicating proton trapping. The oxygen vacancies remained in the oxide have negligible impact on macroscopic proton diffusion, thus proton trapping.

Event date： 2019.6

Language：English  

Venue：PyeongChang Alpensia Resort Convention Center   Country：Korea, Republic of  

Event date： 2019.6

Language：English  

Venue：PyeongChang Alpensia Resort Convention Center   Country：Korea, Republic of  

Event date： 2019.6

Language：English  

Venue：PyeongChang Alpensia Resort Convention Center   Country：Korea, Republic of  

Event date： 2019.6

Language：English  

Venue：PyeongChang Alpensia Resort Convention Center   Country：Korea, Republic of  

Event date： 2019.6

Language：English  

Venue：PyeongChang Alpensia Resort Convention Center   Country：Korea, Republic of  

Event date： 2019.6

Language：English   Presentation type：Oral presentation (general)  

Venue：PyeongChang Alpensia Resort Convention Center   Country：Korea, Republic of  

Event date： 2019.6

Language：English   Presentation type：Oral presentation (general)  

Venue：PyeongChang Alpensia Resort Convention Center   Country：Korea, Republic of  

Event date： 2019.6

Language：English   Presentation type：Oral presentation (general)  

Venue：熊本県民交流館パレア   Country：Japan  

Event date： 2019.6

Language：Japanese  

Venue：熊本県民交流館パレア   Country：Japan  

Event date： 2019.6

Language：Japanese  

Venue：熊本県民交流館パレア   Country：Japan  

Event date： 2019.6

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：熊本県民交流館パレア   Country：Japan  

Event date： 2019.6

Language：Japanese  

Venue：熊本県民交流館パレア   Country：Japan  

Event date： 2019.3

Language：Japanese  

Venue：大阪市立大学   Country：Japan  

Event date： 2019.2

Language：Japanese  

Venue：愛媛大学   Country：Japan  

Event date： 2019.1 - 2019.2

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学   Country：Japan  

Event date： 2019.1 - 2019.2

Language：Japanese  

Venue：九州大学   Country：Japan  

Event date： 2019.1 - 2019.2

Language：Japanese  

Venue：九州大学   Country：Japan  

Event date： 2019.1 - 2019.2

Language：English  

Venue：九州大学   Country：Japan  

Event date： 2018.12

Language：Japanese  

Venue：京都大学   Country：Japan  

Event date： 2018.12

Language：Japanese  

Venue：京都大学   Country：Japan  

Event date： 2018.12

Language：Japanese  

Venue：京都大学   Country：Japan  

Event date： 2018.12

Language：Japanese  

Country：Japan  

Event date： 2018.10

Language：English  

Venue：Columbus   Country：United States  

Event date： 2018.9

Language：English  

Venue：西新プラザ   Country：Japan  

Event date： 2018.9

Language：English  

Venue：西新プラザ   Country：Japan  

Event date： 2018.9

Language：English  

Venue：西新プラザ   Country：Japan  

Event date： 2018.6

Language：Japanese  

Country：Japan  

Event date： 2018.6

Language：Japanese  

Country：Japan  

Event date： 2018.6

Language：Japanese  

Country：Japan  

Event date： 2018.6

Language：English  

Country：Japan  

Event date： 2018.6

Language：English  

Country：Japan  

Event date： 2018.6

Language：Japanese  

Country：Japan  

Event date： 2018.6

Language：Japanese  

Country：Japan  

Event date： 2018.6

Language：Japanese  

Country：Japan  

Event date： 2018.3

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Country：Japan  

Event date： 2018.1

Language：English  

Country：Japan  

Event date： 2018.1

Language：Japanese  

Country：Japan  

Event date： 2018.1

Language：Japanese  

Country：Japan  

Event date： 2018.1

Language：Japanese  

Venue：九州大学   Country：Japan  

Event date： 2017.12

Language：Japanese  

Venue：仙台   Country：Japan  

Event date： 2017.12

Language：Japanese  

Country：Japan  

Event date： 2017.12

Language：Japanese  

Country：Japan  

Event date： 2017.12

Language：Japanese  

Venue：天童   Country：Japan  

Event date： 2017.12

Language：Japanese  

Venue：天童   Country：Japan  

Event date： 2017.12

Language：Japanese  

Country：Japan  

Event date： 2017.11

Language：Japanese  

Venue：佐渡   Country：Japan  

Event date： 2017.9

Language：Japanese  

Country：Japan  

Event date： 2017.9

Language：Japanese  

Venue：宮崎   Country：Japan  

Event date： 2017.9

Language：Japanese  

Venue：松山   Country：Japan  

Event date： 2017.9

Language：Japanese  

Venue：札幌   Country：Japan  

Event date： 2017.7

Language：English  

Venue：Stanford University   Country：United States  

Event date： 2017.7

Language：Japanese  

Venue：北九州   Country：Japan  

Event date： 2017.7

Language：Japanese  

Venue：北九州   Country：Japan  

Event date： 2017.7

Language：Japanese  

Venue：北九州   Country：Japan  

Event date： 2017.6

Language：Japanese  

Country：Japan  

Event date： 2017.6

Language：English  

Venue：Padua, Italy   Country：Italy  

Event date： 2017.6

Language：Japanese  

Venue：Padua   Country：Italy  

Event date： 2017.6

Language：English  

Venue：Oslo   Country：Norway  

Event date： 2017.6

Language：Japanese  

Venue：熊本大学   Country：Japan  

Event date： 2017.6

Language：Japanese  

Venue：熊本大学   Country：Japan  

Event date： 2017.6

Language：Japanese  

Venue：熊本大学   Country：Japan  

Event date： 2017.6

Language：Japanese  

Venue：熊本大学   Country：Japan  

Event date： 2017.5

Language：Japanese  

Venue：Sapporo   Country：Japan  

Event date： 2017.4

Language：Japanese  

Venue：天童   Country：Japan  

Event date： 2017.3

Language：Japanese  

Venue：京都   Country：Japan  

Event date： 2017.3

Language：Japanese  

Venue：八王子   Country：Japan  

Event date： 2017.3

Language：Japanese  

Venue：八王子   Country：Japan  

Event date： 2017.1

Language：Japanese  

Venue：福岡   Country：Japan  

Event date： 2017.1

Language：Japanese  

Country：Japan  

Event date： 2017.1

Language：Japanese  

Venue：福岡   Country：Japan  

Event date： 2017.1

Language：Japanese  

Venue：福岡   Country：Japan  

Event date： 2017.1

Language：Japanese  

Venue：大岡山   Country：Japan  

Event date： 2016.12

Language：Japanese  

Venue：Fukuoka   Country：Japan  

Event date： 2016.12

Language：Japanese  

Venue：名古屋   Country：Japan  

Event date： 2016.12

Language：Japanese  

Venue：名古屋   Country：Japan  

Event date： 2016.10

Language：Japanese  

Venue：東京   Country：Japan  

Event date： 2016.10

Language：English   Presentation type：Oral presentation (general)  

Venue：幕張　in Tokyo   Country：Japan  

Event date： 2016.9

Language：Japanese  

Venue：指宿   Country：Japan  

Event date： 2016.9

Language：Japanese  

Venue：大阪大学   Country：Japan  

Event date： 2016.9

Language：Japanese  

Venue：盛岡   Country：Japan  

Event date： 2016.9

Language：English  

Venue：the Soria Moria conference center in Oslo   Country：Norway  

Event date： 2016.9 - 2018.9

Language：Japanese  

Venue：Santa Fe   Country：United States  

Event date： 2016.9

Language：English   Presentation type：Oral presentation (general)  

Venue：LaFonda on the Plaza, New Mexico,   Country：United States  

Event date： 2016.9

Language：English   Presentation type：Oral presentation (general)  

Venue：Colorado School of Mines   Country：United States  

Event date： 2016.8

Language：Japanese  

Venue：サンメッセ鳥栖   Country：Japan  

Event date： 2016.7

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：茨城   Country：Japan  

Event date： 2016.7

Language：Japanese  

Venue：つくば   Country：Japan  

Event date： 2016.7

Language：Japanese  

Venue：メルパルク京都   Country：Japan  

Event date： 2016.7

Language：Japanese  

Venue：北九州   Country：Japan  

Event date： 2016.7

Language：Japanese  

Venue：北九州   Country：Japan  

Event date： 2016.6

Language：Japanese  

Venue：熊本   Country：Japan  

Event date： 2016.6

Language：Japanese  

Venue：熊本   Country：Japan  

Event date： 2016.6

Language：Japanese  

Venue：熊本   Country：Japan  

Event date： 2016.6

Language：Japanese  

Venue：東京工業大学   Country：Japan  

Event date： 2016.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：同志社大学   Country：Japan  

Event date： 2016.3

Language：Japanese  

Venue：大阪府立大学   Country：Japan  

Event date： 2016.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京理科大学   Country：Japan  

Event date： 2016.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京理科大学   Country：Japan  

Event date： 2016.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京理科大学   Country：Japan  

Event date： 2016.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京理科大学   Country：Japan  

Event date： 2016.3

Language：English   Presentation type：Oral presentation (general)  

Venue：東京理科大学   Country：Japan  

Event date： 2015.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：北海道大学   Country：Japan  

Event date： 2015.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：北海道大学   Country：Japan  

Event date： 2015.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：北海道大学   Country：Japan  

Event date： 2015.11 - 2016.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：首都大学東京   Country：Japan  

Event date： 2015.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学伊都キャンパス   Country：Japan  

Event date： 2015.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学伊都キャンパス   Country：Japan  

Event date： 2015.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：大阪市立大学   Country：Japan  

Event date： 2015.8 - 2015.9

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：静岡県賀茂郡東伊豆町　伊豆熱川温泉   Country：Japan  

Event date： 2015.8 - 2015.9

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：静岡県賀茂郡東伊豆町　伊豆熱川温泉   Country：Japan  

Event date： 2015.8

Language：English   Presentation type：Oral presentation (general)  

Country：United Kingdom  

Event date： 2015.8

Language：English   Presentation type：Oral presentation (general)  

Country：United States  

Event date： 2015.6

Language：English  

Country：United States  

Event date： 2015.6

Language：English  

Country：United States  

Event date： 2015.3

Language：Japanese  

Country：Japan  

Event date： 2014.11

Language：English  

Country：Japan  

Event date： 2014.11

Language：Japanese  

Country：Japan  

Event date： 2014.10

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2014.9

Language：English   Presentation type：Oral presentation (general)  

Country：Korea, Republic of  

Event date： 2014.9

Language：Japanese  

Country：Japan  

Event date： 2014.9

Language：English   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2014.8 - 2014.9

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2014.8

Language：English   Presentation type：Oral presentation (general)  

Country：Germany  

Event date： 2014.5

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2014.4

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2014.3

Language：English   Presentation type：Oral presentation (general)  

Country：United States  

Event date： 2014.3

Language：Japanese  

Country：Japan  

Event date： 2014.3

Language：English  

Country：Japan  

Event date： 2014.2

Language：English  

Country：United States  

Event date： 2013.8

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2013.7

Language：English   Presentation type：Oral presentation (general)  

Country：United Kingdom  

Event date： 2013.7

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2013.7

Language：English   Presentation type：Oral presentation (general)  

Country：United Kingdom  

Event date： 2013.6

Language：English   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2013.6

Language：English  

Country：Japan  

Event date： 2013.5

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2012.12

Language：English  

Country：Japan  

Event date： 2012.11

Language：English  

Country：United States  

Event date： 2012.11

Language：English   Presentation type：Oral presentation (general)  

Venue：九州大学   Country：Japan  

Event date： 2012.11

Language：English   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2012.11

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2012.11

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2012.11 - 2011.11

Language：English   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2012.9

Language：English  

Country：France  

Event date： 2012.5

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2012.4

Language：English  

Country：United States  

Event date： 2012.3

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2012.3

Language：English   Presentation type：Symposium, workshop panel (public)  

Country：Japan  

Event date： 2012.1

Language：English  

Country：Japan  

Event date： 2011.11

Language：English  

Country：United States  

Event date： 2011.7

Language：English  

Country：Poland  

Event date： 2011.7

Language：English  

Country：United States  

Event date： 2011.6

Language：English   Presentation type：Oral presentation (general)  

Country：United States  

Event date： 2011.4

Language：English  

Country：United States  

Event date： 2011.3

Language：English   Presentation type：Symposium, workshop panel (public)  

Country：United States  

Event date： 2010.8

Language：English  

Country：United States  

Event date： 2009.6 - 2009.7

Language：English  

Country：Canada  

Event date： 2008.5

Language：English  

Country：United States  

Event date： 2008.2

Language：English   Presentation type：Symposium, workshop panel (public)  

Country：United States  

Event date： 2006.7

Language：English   Presentation type：Oral presentation (general)  

Venue：フェアモントホテル，バンクーバー   Country：Canada  

Event date： 2006.3

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2005.7

Language：English  

Country：Portugal  

Event date： 2005.3

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2004.6

Language：English  

Country：Poland  

Event date： 2002.10

Language：English  

Country：Japan  

Event date： 2001.12

Language：English  

Country：United States  

Event date： 2001.6

Language：English  

Country：Germany  

Event date： 2001.6

Language：English   Presentation type：Oral presentation (general)  

Country：Germany  

Event date： 2000.6

Language：English  

Country：France  

Event date： 2000.6

Language：English  

Country：Sweden  

Event date： 1999.7

Language：English  

Country：Japan  

Event date： 1999.7

Language：English  

Country：Japan  

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

DOI： https://doi.org/10.11470/oubutsu.88.4_267

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Type：Competition, symposium, etc. 

Type：Peer review 

Number of peer-reviewed articles in foreign language journals：8

Number of peer-reviewed articles in Japanese journals：5

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Number of participants：100

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc.