Browsing by Author "Kartini, E"

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    Derivation of inter-atomic force constants of Cu2O from diffuse neutron scattering measurement
    (Atom Indonesia, 2013-04-15) Makhsun, T; Sakuma, T; Kartini, E; Takahashi, H; Igawa, N; Danilkin, SA; Sakai, R
    Neutron scattering intensity from Cu2O compound has been measured at 10 K and 295 K with High Resolution Powder Diffractometer at JRR-3 JAEA. The oscillatory diffuse scattering related to correlations among thermal displacements of atoms was observed at 295 K. The correlation parameters were determined from the observed diffuse scattering intensity at 10 and 295 K. The force constants between the neighboring atoms in Cu2O were estimated from the correlation parameters and compared to those of Ag2O. (c) 2016 Atom Indonesia.
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    Neutron diffraction study on Li3PO4 solid electrolyte for lithium ion battery
    (Elsevier, 2018-12-15) Kartini, E; Manawan, M; Collins, MF; Avdeev, M
    The solid electrolyte, Li3PO4 has been prepared by a wet chemical reaction. The crystal structure of Li3PO4 was measured at room temperature by a high resolution powder diffraction (HRPD) at the Neutron Scattering Laboratory, National Nuclear Energy Agency (BATAN), Indonesia. Another series of neutron data at 3 K and 300 K were measured by an ECHIDNA at Australian Center for Neutron Scattering, ANSTO, Australia. Based on how neutron and X-rays interact with matter, it is also important to perform the x-ray diffraction on Li3PO4. The purpose is to understand the insight crystal structure of Li3PO4 from two different methods. Both refinement results showed that crystal structure belong to the β-Li3PO4 with orthorhombic phase P m n 21 (31), with the lattice parameters are a = 6.1168 Å, b = 5.2498 Å, c = 4.8723 Å. Fourier method employed to reveal the main difference between neutron and X-rays sources. It is clearly shown that Li atom is visible to neutron. The negative scattering length of Li (−1.90) gave a negative intensity in the neutron Fourier map. In contrast to neutron, X-Ray interacts with electron gave a positive intensity but the heavy atom P dominates the intensity due to its high number of electron. The neutron can provide more detail in the structure information. By comparing the 300 K data with data 3 K, the Li-ions diffusion can be observed from the neutron Fourier maps, and the Li-ions elongation pathway can be seen from the 3-D structure model. It can be concluded here that neutron is an indispensable tool to observe the lithium ion battery materials.© 2017 Elsevier B.V.
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    Reverse Monte-Carlo Analysis of neutron diffraction from AgI–Ag2S–AgPO3 superionic conducting glasses
    (Elsevier B. V., 2006-11-15) Magaraggia, R; Kennedy, SJ; Tedesco, T; Kartini, E; Collins, MF; Itoh, K
    Neutron diffraction patterns from silver phosphate (AgPO3), AgI–AgPO3 and Ag2S–AgPO3 glasses were analysed by the Reverse Monte-Carlo method. The diffraction patterns were collected on the HIT-II spectrometer at KENS up to Å. The derived structural models of the salt-doped glasses were compared to AgPO3 glass to correlate features of the atomic and molecular structure with observed superionic conduction in these glasses. A structural model based on extended chains of PO4 tetrahedra, as reported previously by other researchers, provides a solid basis for all these glasses. The analysis indicates a strengthening of the Ag–Ag correlations and contrasting changes in the Ag–O correlations in the doped glasses. We also conclude that S largely displaces non-bridging O in the PO4 tetrahedra in Ag2S–AgPO3 glass.
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    Visualizing lithium ions in the crystal structure of Li3PO4 by in situ neutron diffraction
    (John Wiley & Sons, Inc, 2021-10) Manawan, M; Kartini, E; Avdeev, M
    Li3PO4 is known to demonstrate Li+ ionic conductivity, making it a good candidate for solid electrolytes in all-solid batteries. Understanding the crystal structure and its connection to Li+ diffusion is essential for further rational doping to improve the ionic transport mechanism. The purpose of this study is to investigate this mechanism using anisotropic displacement parameters (ADPs), nuclear density distribution and bond valence mapping. In situ neutron powder diffraction experiments have been performed using the high-resolution powder diffractometer ECHIDNA at the OPAL reactor, Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, NSW, Australia. The ADPs and nuclear density distribution were determined from the analysis of neutron diffraction data using the Rietveld method, whereas the bond valence map was calculated from the refined structure. The crystal structure remained unchanged as the temperature was increased (3, 100, 300 and 400 K). However, the ADPs show a greater increase in anisotropy in the a and b axes compared with the c axis, indicating the tendency of the ionic movement. By combining nuclear density distribution and bond valence mapping, the most likely lithium-ion diffusion in the crystal structure can be visualized. © International Union of Crystallography