1988 Fiscal Year Final Research Report Summary
Atom-level analysis of structures of lattice defects in materials
| Project/Area Number |
62460187
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Physical properties of metals
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
SAKURAI Junji Hiroshima University,Associate Professor, 理学部, 助教授 (30033814)
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| Co-Investigator(Kenkyū-buntansha) |
KOMURA Yukitomo Technical Institute of Hiroshima University Professor, 基礎教育, 教授 (40033774)
KITANO Yasuyuki Hiroshima University,Associate Professor, 理学部, 助教授 (20033855)
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| Project Period (FY) |
1987 – 1988
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| Keywords | X-ray diffraction / Electron diffraction / High-resolution-electron-microscopy / High-Tc superconductors / Ti-Ni / Super lattice |
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| Research Abstract |
Some materials newly found as well as recently synthesized were examined by not only the X-ray or electron diffraction methods but also the electron microscopy.
High-Tc superconducting materials, Y-Ba-Cu-Oxide: Observations of the microstructures by high-resolution electron microscopy have pointed that the twin-lamellar structures are also important for the quality of the supercon-ductivity. Bi-Ca-Sr-Cu-Oxide: The conditions under which more than 70% of the 107K-class superconducting materials are synthesized without Pb in the pellets of the oxise are determined. The Bi-concentration in the materials is unexpectedly high.
Shape memory alloy, Ti-Ni: Three features in the diffuse scattering have been confirmed. Diffuse maxima locate near n/7, 2n/7, 3n/7 (n an integer) and equivalent positions. A ring-type diffuse scattering is observed in the h01 reciprocal plane and the distribution is found to be reversively changed at low temperatures. All the diffuse scattering disappear in the electron diffraction pattern when the electron beam is incident parallel to the <111>-direction.
[(GaAS)_4/(AlAs)_4]_<150>-Superlattice: The period of the superlattice is not the same throughout the specimen, and fluctuates between eight and nine times of the atomic layer. B19-ordered alloy: Below the phase transition temperature, an interesing domain structure has been discovered. The micro-structures are interpreted by the existence of various types of disclinations. Laves phase alloys: Boundary structure of layer structures are analyzed by proposing an extention of the concept of the CSL-model.
Ce-intermetallic compounds: Various intermetallic compounds containing Ce, have been investigated at low temperatures. Anomalous temperature dependences of the electric resistivities as well as the thermo-electric power have been discovered. Anomaly in the thermal expansion coeffeicients and latticc transformations have also been detected.
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Research Products
(12 results)
