Kyushu University Academic Staff Educational and Research Activities Database
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kazuhiro Yasuda Last modified date:2022.07.04

Professor / Division of Quantum Science of Materials
Department of Applied Quantum Physics and Nuclear Engineering
Faculty of Engineering

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Department ofApplied Quantum Physics and Nuclear Engineering, Kyushu University .
Academic Degree
Dr. of Engineering
Country of degree conferring institution (Overseas)
Field of Specialization
Radiation Damage, Nuclear materials, lattice defects
ORCID(Open Researcher and Contributor ID)
Total Priod of education and research career in the foreign country
Outline Activities
Kazuhiro Yasuda’s research interests are on radiation effects and microstructure development of nuclear materials and energy materials. His works relates (1)the atomic scale structure of radiation-induced defects in ceramics and metals, and its accumulation process and stability, (2) physical mechanism of radiation damag in ionic and covalent materials, (3) Synergy effects of displacement damage and electronic excitation in ionic and covalent materials, and (4) development of "in-situ" experimental method by using high voltage electron microscope to elucidation of the production and kinetics of point defects.
Research Interests
  • Development of in situ observation/measurement technique in HVEM for radiation defects study
    keyword : radiation damage, point defcets, lattice defects, TEM, in situ technique, Cathodoluminescence
    2015.04Factors controlling radiation damage in ceramics.
  • Controlling factor of radiation damage in ceramics
    keyword : radiation damage, point defcets, lattice defects, TEM, mechanical properties
    1995.04~2020.03Factors controlling radiation damage in ceramics.
  • Radiation damage in nuclear fuels, inert matrix for fuel and/or transmutation target
    keyword : fluorite oxide ceramics, selective displacement damage, zirconia, urania, ceria, subdivision of grains
    2002.04Radiation damage in fluorite structure nuclear fuels.
  • Radiation effects in nitride compounds for nuclear fuel applications
    keyword : nitride compounds, ZrN, selective displacement damage, ion track, dislocation loops
    2007.04Radiation damage in fluorite structure nuclear fuels.
  • Synergestic effects of electronic excitation, displacement damage and electric field on radiation damage in ceramics
    keyword : displacement damage, electronic excitation, electrid field, oxide ceramics, TEM, in situ experiments
    2000.04Simultaneous effects of displacement damage, electronic excitaion and electric field in oxide ceramics.
  • Ion beam modification of materials
    keyword : radiation damage, nanosize particles, transmission electron microscopy
    2003.04Ion beam-induced modification of functional materials.
  • radiation effects in zirconium alloys
    keyword : dislocation loop, mibility of defects, oxidation, corrosion, stress, TEM
    2000.04~2004.03Radiation damage and oxidation of zirconium alloys.
Academic Activities
1. M.M.Rahman, T.Yamamoto, S.Matsumura, J.M.Costantini, K.Yasuda, Ab Initio molecular dynamics study of threshold displacement energy in Zirconium Nitride, Journal of Nuclear Materials , 554,, 153076, 2021.05, Zirconium nitride (ZrN) is a promising matrix candidate for advanced nuclear fuels and transmutation of minor actinides. This study investigates the displacement process induced by low-energy recoils in ZrN using ab initio molecular dynamics (AIMD) simulations to evaluate the threshold displacement energy (Ed). Observations of the collision processes of primary knock-on atoms (PKAs) for both Zr and N atoms were performed for seven different directions: [100], [110], [111], [210], [211], [221], and [321], which cover most regions of the stereographic triangle. The values of Ed ranged from 15 eV to 50 eV, and the collision processes were dependent on the crystallographic orientations. The weighted average values of Ed evaluated from the PKA directions investigated in this study were 33 eV and 29 eV for the Zr and N atoms, respectively. Anti-site defects were not formed for either Zr or N PKAs. Sequential replacement collisions along the [110] atomic row played an important role in the collision process, providing a lower value of Ed in the crystallographic directions. Furthermore, configurations of interstitials were different between the Zr and N atoms, which also influenced Ed values..
2. S. Yoshioka, K. Yasuda, S. Matsumura, E. Kobayashi, Transition of Cationic Local Structures in Mg1- xNixAl2O4, The Journal of Physical Chemistry, 125,, 5269-5277, 2021.03, In this study, cationic local structures in the series of MgAl2O4–NiAl2O4 solid solutions (Mg1-xNixAl2O4) were examined using Mg, Al, and Ni K-edge X-ray absorption near-edge structure (XANES). Theoretical calculations of XANES using the all-electron full-potential augmented plane-wave in addition to the local-orbital method were performed to investigate the transition of the cationic local structures depending on their compositions. For the calculations, the atomic coordination was studied using crystal structures of normal and ordered inverse spinels. The experimental spectra of the end members MgAl2O4 and NiAl2O4 were successfully reproduced from the theoretical spectra. Furthermore, the inversion degrees of the end members, analyzed using the calculated spectra, were consistent with previous experimental reports. The Ni2+ ions show three kinds of local structures, and their volume fractions change depending on the composition of Mg1-xNixAl2O4, whereas the Mg2+ ions show two kinds of local structures. The Al3+ ions change the local structure between tetrahedral and octahedral sites to balance the behaviors of Mg2+ and Ni2+ in the compositions. Although the analysis using XANES provides rich information, a theoretical approach is desirable for reliable and quantitative analysis of multication oxides and their disordering..
3. S. Yoshioka, K. Tsuruta, T. Yamamoto, K. Yasuda, S. Matsumura, T. Sugiyama, Y. Oba, N. Ishikawa, E. Kobayashi, K. Okudaira, Local Structure Investigations of Accumulated Damage in Irradiated MgAl2O4, Journal of American Ceramic Society,, 103, 4654-4663, 2020.03, Damaged structures in the MgAl2O4 spinel induced by swift heavy ions were investigated using the X-ray absorption near edge structure (XANES) and small angle X-ray scattering (SAXS). Increasing the fluence of 100 MeV Xe ions leads to increased SAXS intensity and XANES spectral changes on both Mg and Al K-edges. The damaged regions of ion tracks were observed by SAXS to be cylindrical in shapewith a diameter of 5 nm. The theoretical XANES spectra indicated that the changes in the experimental spectra were due to the cationic disordering between tetrahedral and octahedral sites. This disordering caused an increase in the inversion degree of the cations. Furthermore, the quantitative analysis of the XANES spectra revealed the preferential occupation of cations at the octahedral sites at high fluence..
4. J.M. Costantini, P. Seo, K. Yasuda, AKM S.I. Bhuian, T. Ogawa, D. Gourier, Cathodoluminescence of cerium dioxide: Combined effects of the electron beam energy and sample temperature, Journal of luminessence,, 226, 117379, 2020.05, In-situ cathodoluminescence (CL) spectroscopy is used to study point-defect formation in cerium dioxide (CeO2) by high-energy electrons (400 keV-1,250 keV) at ∼100 K, 200 K, and 300 K in a high-voltage electron microscope (HVEM). Complementary CL spectra are also obtained for 20-keV electron excitation at ∼300 K in a scanning electron microscope (SEM). Experiments were carried out on a single crystal and polycrystalline sintered sample. The more prominent and broad emission band centered at a photon energy of ∼4.2 eV is ascribed to F+ centers (oxygen vacancies) produced by the high-energy electron irradiation. Two other weaker CL bands centered at ∼2.3–2.4 eV and 2.8–2.9 eV at 300 K are related to trivalent cerium ions, corresponding to 5d → 4f radiative transitions, regardless of electron energy. Similar spectra are recorded at 100 K and 200 K, yet with shifts and broadening of the latter emission bands. A maximum of all CL bands is found at ∼600 keV electron energy for the polycrystalline sample regardless of temperature, and for the single crystal at 300 K. In contrast, a continuous increase versus electron energy is observed for the 4.2-eV band of the single crystal at 100 K and 200 K above a threshold corresponding to the oxygen displacement energy. The dependence of CL intensities on the primary electron energy is analyzed on the basis of the interplay of the luminescence cross section and oxygen displacement cross section. The electron energy dependence of ionization cross sections is addressed by relying on secondary electron spectra computed with the PHITS code which is benchmarked against other computer codes such as PENELOPE, as implemented in Geant4. The F+ center band intensity is strongly reduced in the polycrystalline sample with respect to the single crystal in the same irradiation conditions regardless of temperature due to grain boundaries.
5. T. Yamamoto, A. Chartier, K. Yasuda, C. Meis, K. Shiiyama and S. Matsumura, Molecular Dynamics Simulation of Point Defect Accumulation in MgAl2O4, Nucl. Instr. and Meth. Phys. Res., B, 266、pp.2676-2682, 2008.05.
6. K. Yasuda, T. Yamamoto, S. Seki, K. Shiiyama and S. Matsumura, Production and Stability of Radiation-Induced Defects in MgAl2O4 under Electronic Excitation, Nucl. Instr. and Meth. Phys. Res., B, 266、pp.2834-2841, 2008.05.
7. Kazuhiro Yasuda, Tomokazu Yamamoto and Syo Matsumura, The Atomic Structure of Disordered Ion Tracks in Magnesium Aluminate Spinel, Journal of Materials, (2007) 27, 2007.04.
8. K. Yasuda, T. Yamamoto, M. Shimada, S. Matsumura, Y. Chimi and N. Ishikawa, ‘, Atotic structure and disordering induced by 350 MeV Au ions in MgAl2O4, Nucl. Instr. and Meth. Phys. Res., B, 250 (2006) 238, 2006.12.
9. T. Yamamoto, M. Shimada, K. Yasuda, S. Matsumura, Y. Chimi and N. Ishikawa, Microstructure and atomic disordering of magnesium aluminate spinel irradiated with swift heavy ions, Nucl. Instr. and Meth. Phys. Res., B, 245 (2006) 235, 2006.12.
Works, Software and Database
1. Simultaneous irradiation effects with ions and electrons on materials.
Educational Activities
Lattice Defects in Materials(Global Course of Department of Applied Quantum Physics and Nuclear Engineering)
Other Educational Activities
  • 2021.04.