Nihon Kessho Gakkaishi
Online ISSN : 1884-5576
Print ISSN : 0369-4585
ISSN-L : 0369-4585
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Volume 54, Issue 3
Displaying 1-15 of 15 articles from this issue
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Review Articles
Articles
  • Effects of Randomness and Frustration on the Relaxor Nature in Pb(In1/2Nb1/2)O3
    Kenji OHWADA
    2012 Volume 54 Issue 3 Pages 147-154
    Published: June 30, 2012
    Released on J-STAGE: July 03, 2012
    DOIhttps://doi.org/10.5940/jcrsj.54.147
    JOURNAL FREE ACCESS
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    It is well known that B-site randomness contributes to the appearance of relaxor phenomena in the lead-based complex perovskite Pb(B'B")O3. But the microscopic mechanism of the effect of B-site randomness on the systems has not been understood yet. Among the Pb(B'B")O3 systems, Pb(In1/2Nb1/2)O3(PIN) has drawn much attention because it can be in the antiferroelectric (AFE), ferroelectric (FE), or relaxor state depending on B-site randomness. We review the recent progress in our understanding of the effect of B-site randomness on PIN from the experimental viewpoint. As a conclusion of the arguments, we also introduce the frustration mechanism in Pb(B'B")O3.
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Articles
  • Atomic Pair Distribution Function (PDF) Analysis of Ferroelectric Materials
    Yasuhiro YONEDA
    2012 Volume 54 Issue 3 Pages 155-158
    Published: June 30, 2012
    Released on J-STAGE: July 03, 2012
    DOIhttps://doi.org/10.5940/jcrsj.54.155
    JOURNAL FREE ACCESS
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    Atomic Pair Distribution Function (PDF) is a one of local structure analysis. PDF analysis is a powerful method for ferroelectrics in which domain structure exists. A deviation arises between average and local structures under the influence of the ferroelectric domain configuration. The local structure analysis of BaTiO3 and BiMg0.5Ti0.5O3 is shown as an example of application to the ferroelectric materials of PDF analysis.
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  • Structural Analysis at an Atomic Scale Using Spherical Aberration Corrected Electron Microscope
    Yoshifumi OSHIMA, Yasumasa TANISHIRO, Takayuki TANAKA, Kunio TAKAYANAG ...
    2012 Volume 54 Issue 3 Pages 159-165
    Published: June 30, 2012
    Released on J-STAGE: July 03, 2012
    DOIhttps://doi.org/10.5940/jcrsj.54.159
    JOURNAL FREE ACCESS
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    Recently, a new spherical aberration corrected electron microscope called as R005 has been developed. Since very sharp electron probe of 30 mrad in convergent semi-angle is realized, the special resolution reaches to 47 pm in scanning transmission electron microscopy, which is the world best performance. In this review, we show that lithium ions are visualized in the spinel structure using R005. We found that the number of lithium atoms at the column was countable. In addition, we show that individual arsenic and antimony dopant atoms in the silicon crystal three-dimensionally.
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  • Structure of Atg7 Alone and its Atg8-Bound Forms
    Nobuo NODA
    2012 Volume 54 Issue 3 Pages 166-171
    Published: June 30, 2012
    Released on J-STAGE: July 03, 2012
    DOIhttps://doi.org/10.5940/jcrsj.54.166
    JOURNAL FREE ACCESS
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    Atg7 is a noncanonical E1 enzyme that activates Atg8 and transfers it to Atg3 (E2 enzyme), thus playing an essential role in conjugating Atg8 with phosphatidylethanolamine and thus in autophagy. Atg7 protomer is comprised of two globular domains, the N-terminal domain (NTD) and the C-terminal domain (CTD), and forms a homodimer through CTD. Atg7-Atg8 complex structures and biochemical analyses revealed that Atg8 is initially recognized by the C-terminal tail of CTD and is then transferred to the adenylation domain in CTD, where Atg8 Gly116 is adenylated and thioester-linked to the catalytic cysteine of Atg7. Atg8 is then transferred to Atg3 bound to the NTD of the opposite protomer within an Atg7 dimer via a trans mechanism.
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  • Magnetic and Dielectric Clusters in BiFeO3-BaTiO3
    Minoru SODA
    2012 Volume 54 Issue 3 Pages 172-177
    Published: June 30, 2012
    Released on J-STAGE: July 03, 2012
    DOIhttps://doi.org/10.5940/jcrsj.54.172
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    A new class of superparamagnetism was found in relaxor ferroelectrics having magnetic ions 2/3BiFeO3-1/3BaTiO3. The polar nanoregion (PNR), which governs the relaxor ferroelectric property, affects the magnetic ordering significantly, and the resulting magnetic nano-domains are the new origin of superparamagnetism. The temperature variations in the sizes of the magnetic domains and PNRs estimated by our neutron diffraction measurements support this picture. The superparamagnetism induced by PNR is very unique because of its inherent connection between dielectric and magnetic properties.
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  • Polarized Neutron Diffraction Study on a Paramagnetic Cobalt Compound
    Hiroshi SAKIYAMA
    2012 Volume 54 Issue 3 Pages 178-183
    Published: June 30, 2012
    Released on J-STAGE: July 03, 2012
    DOIhttps://doi.org/10.5940/jcrsj.54.178
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    Polarized neutron diffraction (PND) investigations were conducted for a single-crystal of a dinuclear octahedral high-spin cobalt(II) complex, using the local site susceptibility tensor method. The local induced magnetic moments were observed on cobalt(II) ions, revealing an angle of 37(1)°. Previously the compound was found to show a characteristic magnetic behavior, which was thought to be due to the significant magnetic anisotropy caused by an angle between the local axes of cobalt(II) ions. The angle obtained by PND was in good agreement with the result of magnetic analysis, and PND methods were shown to be very useful for studying highly-anisotropic molecular paramagnetic compounds.
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  • Microstructural Analysis of Ferroelectric Oxides by Electron Microscopy
    Shigeo MORI, Yasumasa KOYAMA
    2012 Volume 54 Issue 3 Pages 184-189
    Published: June 30, 2012
    Released on J-STAGE: July 03, 2012
    DOIhttps://doi.org/10.5940/jcrsj.54.184
    JOURNAL FREE ACCESS
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    We have investigated nanoscaled domain configuration of Pb(Ti1-xZrx)O3 (PTZ) and (1-x)Pb(Mg1/3Nb2/3)O3- xPbTiO3 ((1-x)PMN-xPT) in the monoclinic phase around a morphotropic phase boundary (MPB) region thoroughly by means of a transmission electron microscopy (TEM), in order to clarify mechanism of the enhancement of the piezoelectric effect. Two types of domain structures with inhomogeneous configuration were found around the MPB region. One is domain structures characterized by the formation of the nanoscaled herringbone-type domain structures with the ~10 nm width inside the macroscopic-sized banded domains with the 100~200 nm width. The other is as an aggregation of nanoscaled domains with the average size of about 10 nm. An in-situ TEM observation revealed that these nanoscaled domain structures are inherent to the monoclinic phase, which should be responsible for the excellent piezoelecrtric response.
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