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Journal Articles

Inter atomic force constants of $$beta$$-PbF$$_{2}$$ from diffuse neutron scattering measurement

Xianglian*; Bao, W.*; Guo, T.*; Li, P.*; Sakuma, Takashi*; Igawa, Naoki

International Journal of Innovation in Science and Mathematics, 5(6), p.165 - 167, 2017/11

Diffuse neutron scattering measurements were performed on powder $$beta$$-PbF$$_{2}$$ at 633 K. Oscillatory diffuse scattering intensities were observed and the observed diffuse scattering intensities were explained by including the correlation effects among thermal displacements of atoms. The force constants among first- and second-nearest-neighboring atoms in $$beta$$-PbF$$_{2}$$ calculated from the values of correlation effects and Debye-Waller temperature parameters were determined as 0.36 eV/ $AA $^{2}$$ at ${it r}$ = 2.599 ${AA}$ and 0.21 eV/ $AA $^{2}$$ at ${it r}$ = 3.001 AA, respectively.

Journal Articles

Inter-atomic force constants of BaF$$_{2}$$ by diffuse neutron scattering measurement

Sakuma, Takashi*; Makhsun*; Sakai, Ryutaro*; Xianglian*; Takahashi, Haruyuki*; Basar, K.*; Igawa, Naoki; Danilkin, S. A.*

AIP Conference Proceedings 1656, p.020002_1 - 020002_4, 2015/04

 Times Cited Count:1 Percentile:51.16

Diffuse neutron scattering measurement on BaF$$_{2}$$ crystals was performed at 10 K and 295 K. Oscillatory form in the diffuse scattering intensity of BaF$$_{2}$$ was observed at 295 K. The correlation effects among thermal displacements of F-F atoms were obtained from the analysis of oscillatory diffuse scattering intensity. From the values of correlation effects and Debye-Waller temperature parameters, force constants among the first and second nearest neighboring atoms of BaF$$_{2}$$, were determined to be 4.40 and 2.30 eV/$AA$^{2}$$ at 295 K, respectively

Journal Articles

Inter-atomic force constants of Ag$$_{2}$$O from diffuse neutron scattering measurement

Wada, Tamotsu*; Sakuma, Takashi*; Sakai, Ryutaro*; Uehara, Hiroyuki*; Xianglian*; Takahashi, Haruyuki*; Kamishima, Osamu*; Igawa, Naoki; Danilkin, S. A.*

Solid State Ionics, 225, p.18 - 21, 2012/10

 Times Cited Count:6 Percentile:31.07(Chemistry, Physical)

Diffuse neutron scattering measurement on Ag$$_{2}$$O crystals was performed at 8 K and 295 K. The observed diffuse scattering intensities were analyzed by including the correlation effects among thermal displacements of atoms in Ag$$_{2}$$O. Using the values of correlation effects among neighboring atoms and the values of Debye-Waller temperature parameter, force constants among first, second and third nearest neighboring atoms have been evaluated.

Journal Articles

Inter-atomic force constants from correlation effects among thermal displacement of atoms in PbTe

Xianglian*; Sakuma, Takashi*; Mohapatra, S. R.*; Uehara, Hiroyuki*; Takahashi, Haruyuki*; Kamishima, Osamu*; Igawa, Naoki

Molecular Simulation, 38(5), p.448 - 451, 2012/04

 Times Cited Count:1 Percentile:3.23(Chemistry, Physical)

Diffuse neutron scattering measurements have been performed on powder PbTe at 10 and 294 K. Oscillatory diffuse scattering intensity is clearly observed at 294 K. Oscillatory form of the diffuse neutron scattering intensity for PbTe was explained on inclusion of correlation effects among thermal displacements of atoms. From the values of correlation effects and Debye-Waller temperature parameter, force constants among the first nearest neighboring atoms was calculated, $$alpha$$ $$_{rm Pb-Te}$$ = 215 eV/nm$$^{2}$$, and the second ones were $$alpha$$ $$_{rm Pb-Pb}$$ =108 eV/nm$$^{2}$$ and $$alpha$$ $$_{rm Te-Te}$$ = 144 eV/nm$$^{2}$$ at 294 K.

Journal Articles

Correlation effects among thermal displacements of atoms in KBr

Sakuma, Takashi*; Xianglian*; Shimizu, Norifumi*; Mohapatra, S. R.*; Isozaki, Nobuhiro*; Uehara, Hiroyuki*; Takahashi, Haruyuki*; Basar, K.*; Igawa, Naoki; Kamishima, Osamu*

Solid State Ionics, 192(1), p.54 - 57, 2011/06

 Times Cited Count:11 Percentile:48.1(Chemistry, Physical)

Diffuse neutron scattering measurements have been performed on powder KBr. The oscillatory scheme of the diffuse scattering intensity is explained by the values of correlation effects among thermal displacements of 1st, 2nd and 3rd nearest neighboring atoms which are almost the same as those in other ionic crystals. Force constants among 1st, 2nd and 3rd nearest neighboring atoms are obtained from the correlation effects at 90 K are 0.83 eV/$AA $^{2}$$, 0.50 eV/$AA $^{2}$$ and 0.41 eV/$AA $^{2}$$, respectively.

Journal Articles

Force constants of Cu crystals from diffuse neutron scattering measurement

Sakuma, Takashi*; Mohapatra, S. R.*; Uehara, Hiroyuki*; Sakai, Ryutaro*; Xianglian*; Takahashi, Haruyuki*; Igawa, Naoki; Basar, K.*

Atom Indonesia, 36(3), p.121 - 124, 2010/12

Diffuse neutron scattering measurement on Cu crystals was performed at 10 K and 300 K and the observed diffuse scattering intensities were analyzed by including the correlation effects among thermal displacements of atoms in the theory. Using the values of correlation effects among neighboring atoms and the values of Debye-Waller temperature parameter, force constants among first, second and third nearest neighboring atoms had been evaluated. The estimated values of force constants among first, second and third nearest neighboring atoms of Cu were 5.58, 3.63 and 2.37 eV/${AA}$ $$^{2}$$ at 300 K, respectively. The relation between correlation effects and the inter-atomic distance is not depending much on the crystal binding types.

Journal Articles

Diffuse neutron scattering calculation of spinel structure of LiMn$$_{2}$$O$$_{4}$$

Basar, K.*; Xianglian*; Sakuma, Takashi*; Takahashi, Haruyuki*; Abe, Osami*; Igawa, Naoki

AIP Conference Proceedings 1244, p.129 - 135, 2010/06

 Times Cited Count:0 Percentile:0.07

Neutron scattering experiment has been performed on powder LiMn$$_{2}$$O$$_{4}$$ with spinel structure at room temperature. The profile of diffuse scattering was analyzed including the correlation effects among thermal displacement of atoms Li-Li, Li-Mn, Li-O, Mn-Mn, Mn-O and O-O. It was found that the main contribution to the oscillatory profile of diffuse scattering intensity of LiMn$$_{2}$$O$$_{4}$$ was O-O pairs.

Journal Articles

Diffuse scattering of $$gamma$$-PbF$$_{2}$$

Xianglian*; Sakuma, Takashi*; Basar, K.*; Takahashi, Haruyuki*; Igawa, Naoki

Journal of the Physical Society of Japan, 79(Suppl.A), p.29 - 32, 2010/03

 Times Cited Count:0 Percentile:0(Physics, Multidisciplinary)

$$gamma$$-PbF$$_{2}$$ belongs to cubic structure with disordered arrangements of F atoms and shows high ionic conductivity at high temperature. Neutron diffuse scattering intensity measurement has been performed at 773 K. Strong and oscillatory diffuse scattering intensity has been observed. The diffuse scattering can be explained by the correlation effects among thermal displacements of atoms and the short-range order in disordered arrangements of F atoms.

Journal Articles

Estimation of inter-atomic force constants and phonon dispersion using correlation effects among thermal displacement of atoms in Ge

Sakuma, Takashi*; Mohapatra, S. R.*; Isozaki, Nobuhiro*; Uehara, Hiroyuki*; Xianglian*; Basar, K.*; Takahashi, Haruyuki*; Kamishima, Osamu*; Igawa, Naoki

Journal of Non-Crystalline Solids, 357(2), p.559 - 562, 2010/01

 Times Cited Count:2 Percentile:18.17(Materials Science, Ceramics)

The oscillatory diffuse scattering intensity of Ge was observed by neutron scattering measurement. The force constants among the first, second and third nearest neighboring atoms in Ge were determined from the values of correlation effects and Debye-Waller temperature parameters. The inter-atomic force constants among the first, second and third nearest neighboring atoms at 80 K in Ge are 363 eV/nm$$^{2}$$, 232 eV/nm$$^{2}$$ and 200 eV/nm$$^{2}$$, respectively.

Journal Articles

Correlation effects among thermal displacements of atoms from diffuse neutron scattering measurements

Sakuma, Takashi*; Mohapatra, S. R.*; Yokokawa, Jo*; Shimizu, Norifumi*; Isozaki, Nobuhiro*; Uehara, Hiroyuki*; Xianglian*; Basar, K.*; Takahashi, Haruyuki*; Kamishima, Osamu*; et al.

Proceedings of 12th Asian Conference on Solid State Ionics and 15th Chinese Conference on Solid State Ionics, p.439 - 445, 2010/00

Diffuse neutron scattering intensities from ionic crystals, covalent crystals and metal crystals are analyzed by including the correlation effects among thermal displacements of atoms into the function describing background intensity. The obtained values of correlation effects among first nearest neighboring atoms are 0.7 near room temperature. The values of the correlation effects do not depend much on the type of the crystal binding near room temperature. The values of correlation effects decrease rapidly with the increase of inter-atomic distances. The correlation effects also decrease with the decrease of temperature.

Journal Articles

Correlation effects among thermal displacements of atoms in VSe by diffuse neutron scattering measurement

Sakuma, Takashi*; Xianglian*; Siagian, S.*; Basar, K.*; Takahashi, Haruyuki*; Igawa, Naoki; Kamishima, Osamu*

Journal of Thermal Analysis and Calorimetry, 99(1), p.173 - 176, 2009/10

 Times Cited Count:3 Percentile:14.32(Thermodynamics)

Neutron diffraction measurements have been performed on powder VSe at 294 K. The diffuse scattering theory including correlation effects among thermal displacements of atoms is applied to background function in the rietveld analysis. The oscillatory scheme of the diffuse scattering intensity from hexagonal VSe is explained by the correlation effects among far-neighboring Se-Se atoms. The values of the correlation effects depend on the inter-atomic distance and not on the crystal structure.

Journal Articles

Diffuse neutron scattering of KBr at room temperature and its application as background function in rietveld analysis

Basar, K.*; Xianglian*; Sakuma, Takashi*; Takahashi, Haruyuki*; Igawa, Naoki

ITB Journal of Science, 41A(1), p.50 - 58, 2009/05

Diffuse neutron scattering profile of KBr at room temperature was explained by including the correlation among thermal displacement of atoms up to third neighbor atom in the crystal KBr. The values of correlation effects decrease with inter-atomic distance. The diffuse scattering theory including correlation effects is applied as background function in Rietveld analysis.

Journal Articles

Inter-atomic distance and temperature dependence of correlation effects among thermal displacements

Xianglian*; Siagian, S.*; Basar, K.*; Sakuma, Takashi*; Takahashi, Haruyuki*; Igawa, Naoki; Ishii, Yoshinobu*

Solid State Ionics, 180(6-8), p.480 - 482, 2009/05

 Times Cited Count:3 Percentile:18.05(Chemistry, Physical)

Correlation effects among thermal vibrations of atoms are very important to realize the thermal properties of materials. We discuss the inter-atomic distance and temperature dependence of the correlation effects in ionic crystal, AgBr, CuBr, CuI and CuCl, by neutron diffraction method. From the Rietveld analysis of those diffraction data the lattice constants and Deby-Waller parameters were determined. The diffuse scattering of diffraction data was analyzed with the correlation effect, $$mu$$. It is found that the $$mu$$ is 0.6-0.75 for the inter-atomic distance around 2.5${AA}$ and 0.4-0.5 for 4${AA}$ for all ionic crystals. The value of $$mu$$ decreases with the decrease of temperature.

Journal Articles

Correlation effects among atomic thermal displacements in oscillatory diffuse neutron scattering of ZnSe

Basar, K.*; Siagian, S.*; Xianglian*; Sakuma, Takashi*; Takahashi, Haruyuki*; Igawa, Naoki

Nuclear Instruments and Methods in Physics Research A, 600(1), p.237 - 239, 2009/02

 Times Cited Count:9 Percentile:56.98(Instruments & Instrumentation)

Neutron scattering measurements have been performed on powder ZnSe at 15, 150 and 300 K. The oscillatory diffuse neutron scattering intensity is explained by including the correlation effects among atomic thermal displacement of the first, second and third nearest neighboring atoms. It was found that the values of correlation effects decrease by increasing inter-atomic distances and with the decrease of temperature.

Journal Articles

Anneal temperature effect on crystallite size and electric conductivity of LiMn$$_{2}$$O$$_{4}$$

Basar, K.*; Xianglian*; Siagian, S.*; Ohara, Kota*; Sakuma, Takashi*; Takahashi, Haruyuki*; Abe, Osami*; Igawa, Naoki; Ishii, Yoshinobu*

Indonesian Journal of Physics, 20(1), p.9 - 11, 2009/01

Nanosized LiMn$$_{2}$$O$$_{4}$$ has been successfully prepared by solid state reaction of LiOH and MnO$$_{2}$$. Neutron scattering experiments at room temperature and conductivity measurement have been performed on the samples. Anneal temperature effect on the crystallite size and electric conductivity of LiMn$$_{2}$$O$$_{4}$$ is analyzed. The average crystallite size is obtained from the full width at half maximum (FWHM) of Bragg lines using Scherrer equation. The average crystallite size increases with the increase of anneal temperature. Activation energy and conductivity prefactor increase with anneal temperature.

Journal Articles

Effect of Pb-Pb correlation in diffuse scattering of powder PbF$$_{2}$$

Xianglian*; Basar, K.*; Honda, Hiroyuki*; Siagian, S.*; Ohara, Kota*; Sakuma, Takashi*; Takahashi, Haruyuki*; Igawa, Naoki; Ishii, Yoshinobu*

Solid State Ionics, 179(21-26), p.776 - 779, 2008/09

 Times Cited Count:2 Percentile:12.76(Chemistry, Physical)

Diffuse X-ray and neutron scattering from powder PbF$$_{2}$$ are measured at 15 and 294K. Those oscillatory profile of diffuse scattering is explained by including the correlation effects among thermal displacements of atoms. The contribution of correlated thermal vibration of Pb-Pb atoms located at far-off distance to the oscillatory profile of diffuse scattering intensities is first confirmed.

Journal Articles

Oscillatory diffuse scattering study by time-of-flight neutron scattering

Basar, K.*; Xianglian*; Siagian, S.*; Sakuma, Takashi*; Takahashi, Haruyuki*; Yonemura, Masao*; Kamiyama, Takashi*; Ishigaki, Toru*; Igawa, Naoki

Physica B; Condensed Matter, 403(17), p.2557 - 2560, 2008/08

 Times Cited Count:2 Percentile:12.76(Physics, Condensed Matter)

Diffuse scattering is an important tool for analyzing disordered arrangement of atoms in crystals. In this study the oscillatory of diffuse scattering intensity of PbF$$_{2}$$ was observed both in wavelength-dispersive and angular-dispersive neutron scattering measurements, and we discuss the diffuse neutron scattering intensity by TOF measurement on powder sample of PbF$$_{2}$$ compared with those by angular-dispersive diffraction patterns. The diffuse scattering theory including the correlation effects among thermal displacements of atoms is effective for the treatment of diffuse background intensity obtained by TOF neutron experiment.

Journal Articles

Diffuse scattering study of thermal disorder in solid state ionics

Sakuma, Takashi*; Xianglian*; Basar, K.*; Siagian, S.*; Shimizu, Norifumi*; Takahashi, Haruyuki*; Igawa, Naoki

Proceedings of 11th Asian Conference on Solid State Ionics, p.45 - 52, 2008/00

The diffuse neutron scattering intensities for CuI and AgBr were analyzed by the theory including the thermal correction effects up to 3rd nearest neighboring atoms. When we include the temperature dependence of the values of correlation effects, the obtained results by the refinement were improved than the former. The values of correlation effects decrease rapidly with the increase of inter-atomic distance. The values also decrease with the decrease of temperature.

Journal Articles

Neutron scattering study of LiNiO$$_2$$

Basar, K.*; Xianglian*; Honda, Hiroyuki*; Sakuma, Takashi*; Takahashi, Haruyuki*; Abe, Osami*; Igawa, Naoki; Ishii, Yoshinobu

Proceedings of 10th Asian Conference on Solid State Ionics, p.121 - 128, 2006/00

no abstracts in English

Journal Articles

Diffuse X-ray and neutron scattering from powder PbS

Xianglian*; Basar, K.*; Honda, Hiroyuki*; Hojo, Tomoyuki*; Sakuma, Takashi*; Takahashi, Haruyuki*; Igawa, Naoki; Ishii, Yoshinobu

Proceedings of 10th Asian Conference on Solid State Ionics, p.185 - 192, 2006/00

no abstracts in English

25 (Records 1-20 displayed on this page)