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Nagao, Tatsuya*; Igarashi, Junichi
Journal of the Physical Society of Japan, 72(9), p.2381 - 2384, 2003/09
Times Cited Count：10 Percentile：55.03(Physics, Multidisciplinary)We examine the mechanism of the X-ray diffraction process by including the Thomson scattering (TS) term in addition to the resonant X-ray scattering (RXS) term near the Ce L absorption edge in the antiferroquadrupole (AFQ) ordering phase of CeB. Assuming the AFQ order in the 4f states but without any lattice distortion, we obtain the TS intensity comparable to the RXS intensity, owing to the anisotropic charge distribution of 4f states. The present calculation reproduces well the interference pattern between the TS and RXS terms for the (5/2,3/2,3/2) spot observed in the recent experiment. The result suggests that the TS signal as well as the main peak of the RXS signal are a direct reflection of the AFQ order in CeB.
edge of Mn
GaCTakahashi, Manabu*; Igarashi, Junichi
Physical Review B, 67(24), p.245104_1 - 245104_5, 2003/06
Times Cited Count：23 Percentile：70.62(Materials Science, Multidisciplinary)We theoretically investigate the origin of the X-ray magnetic circular dichroism (XMCD) spectra at the K edge of Mn and Ga in the ferromagnetic phase of MnGaC on the basis of an ab initio calculation. Taking account of the spin-orbit interaction in the LDA scheme, we obtain the XMCD spectra in excellent agreement with the recent experiment. We have analyzed the origin of each structure, and thus elucidated the mechanism of inducing the orbital polarization in the p symmetric states. We also discuss a simple sum rule connecting the XMCD spectra with the orbital moment in the p symmetric states.
CIgarashi, Junichi; Nagao, Tatsuya*
Journal of the Physical Society of Japan, 72(5), p.1279 - 1286, 2003/05
Times Cited Count：13 Percentile：61.11(Physics, Multidisciplinary)We study the resonant X-ray scattering (RXS) spectra at the Dy L_
absorption edge in the quadrupolar ordering phase of DyBC. Analyzing the buckling of sheets of B and C atoms, we construct an effective model that the crystal field is acting on the 5d and 4f states with the principal axes different for different sublattices. Treating the 5d states as a band and the 4f states as localized states, we calculate the spectra within the dipole transition. We take account of processes that (1) the lattice distorion directly modulates the 5d states and (2) the charge anisotropy of the quadrupole ordering 4f states modulates the 5d states through the 5d-4f Coulomb interaction. The former process is found to give dominant contribution to the spectra.
Takahashi, Manabu*; Igarashi, Junichi
Physica B; Condensed Matter, 329-333(Part2), p.870 - 871, 2003/05
Times Cited Count：2 Percentile：15.16(Physics, Condensed Matter)We study the resonant X-ray scattering (RXS) spectra around the Cu K edge in KCuF on the basis of the band structure calculation combined with the LDA+U approximation. The lattice distortion is introduced as inputs of the calculation. We reproduce well the experimental spectra as a function of photon energy around the main--K--edge (MKE). The spectral structure around the MKE is independent of the magnetic order (MO) and the orbital order (OO) but strongly dependent on the magnitude of the Jahn--Teller distortion (JTD).
CNagao, Tatsuya*; Igarashi, Junichi
Physica B; Condensed Matter, 329-333(Part2), p.628 - 630, 2003/05
Times Cited Count：5 Percentile：31.44(Physics, Condensed Matter)For elucidating the relation between the resonant X-ray scattering (RXS) signal and the orbital order, we calculate the RXS spectra near the Dy L
absorption edge in DyBC, in the antiferro-quadrupole (AFQ) ordering phase. Using a microscopic model that the 4f states of Dy are atomic while the 5d states form an energy band with a reasonable density of states, we obtain sufficient RXS intensities on the AFQ superlattice spot assuming the quadrupole order in the 4f states but without any lattice distortion, in good agreement with the recent experiment. The present result demonstrates the mechanism that the intensity is brought about by the modulation of 5d states through the anisotropic term of the 5d-4f Coulomb interaction.
Takahashi, Manabu*; Usuda, Manabu; Igarashi, Junichi
Physical Review B, 67(6), p.064425_1 - 064425_7, 2003/02
Times Cited Count：21 Percentile：68.23(Materials Science, Multidisciplinary)We study the magnetic resonant X-ray scattering (RXS) spectra around the K edge of Cu in KCuF on the basis of an ab initio calculation. We use the full-potential linearlized augumented plane wave method in the LDA+U scheme, and introduce the lattice distortion as inputs of the calculation. We obtain finite intensity on magnetic superlattice spots by taking account of the spin-orbit interaction. We also calculate the RXS intensity on orbital superlattice spots. It is found that the intensity increases with increasing Jahn-Teller distortion.
Zhao, L.; Mitomo, Hiroshi*; Nagasawa, Naotsugu; Yoshii, Fumio; Kume, Tamikazu
Carbohydrate Polymers, 51(2), p.169 - 175, 2003/01
Times Cited Count：115 Percentile：96.32(Chemistry, Applied)no abstracts in English
Suhartini, M.; Mitomo, Hiroshi*; Nagasawa, Naotsugu; Yoshii, Fumio; Kume, Tamikazu
Journal of Applied Polymer Science, 88(9), p.2238 - 2246, 2003/00
Times Cited Count：46 Percentile：79.83(Polymer Science)no abstracts in English
Chen, J.; Hasegawa, Shin; Ohashi, Hitoshi; Maekawa, Yasunari; Yoshida, Masaru; Katakai, Ryoichi; Tsubokawa, Norio*
Macromolecular Rapid Communications, 23(2), p.141 - 144, 2002/01
Times Cited Count：9 Percentile：33.27(Polymer Science)no abstracts in English
Suhartini, M.; Mitomo, Hiroshi*; Yoshii, Fumio; Nagasawa, Naotsugu; Kume, Tamikazu
Journal of Polymers and the Environment, 9(4), p.163 - 171, 2001/10
Times Cited Count：25 Percentile：66.18(Engineering, Environmental)no abstracts in English
Hendri, J.*; Hiroki, Akihiro*; Maekawa, Yasunari; Yoshida, Masaru; Katakai, Ryoichi*
Radiation Physics and Chemistry, 61(2), p.155 - 161, 2001/05
Times Cited Count：2 Percentile：19.66(Chemistry, Physical)no abstracts in English
