| Project/Area Number |
10450255
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural/Functional materials
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| Research Institution | THE UNIVERSITY OF TOKYO |
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Principal Investigator |
YAMAMOTO Takahisa The University of Tokyo, Engineering Research Institute, Research Associate, 大学院・工学系研究科, 助手 (20220478)
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| Co-Investigator(Kenkyū-buntansha) |
IKUHARA Yuichi The University of Tokyo, Engineering Research Institute, Associate Professor, 大学院・工学系研究科, 助教授 (70192474)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥12,100,000 (Direct Cost: ¥12,100,000)
Fiscal Year 1999: ¥4,700,000 (Direct Cost: ¥4,700,000)
Fiscal Year 1998: ¥7,400,000 (Direct Cost: ¥7,400,000)
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| Keywords | BaTiOィイD23ィエD2 / Bicrystal / Abnormal grain growth / Electrical properties / PTCR / I-V properties / SrTiOィイD23ィエD2 / Potential Barriers / チタン酸バリウム / 半導体 / ショットキーバリヤ / ポテンシャルバリヤ / 粒界構造 / 結晶粒界 / MREM / EELS |
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| Research Abstract |
BaTiOィイD23ィエD2, Which is often used as based materials for electroceramics, exhibits semiconduction when it is doped with cations whose valence is large than host cations' valence. In general, most of electroceramics are utilized for practical use as in polycrystals and their electrical properties is often closely related to their grain boundary phenomena. Therefore, it must be necessary to investigate the electrical properties directly at single grain boundaries. In this study, BaTiOィイD23ィエD2 bicrystals were fabricated and then their electrical properties were examined. The following results could be obtained.
(1) It was succeeded in construction of the technique for controlling the abnormal grain growth in BaTiOィイD23ィエD2 by changing A/B-site ratio. Coarse-grained structure with a grain size of about 1mm could be obtained.
(2) It was found that the electrical properties in BaTiOィイD23ィエD2 bicrystal closely depend on the grain orientation relationship. The magnitude of Positive temperature coefficient of resistivity effect decerases with an increase in the coherency at grain boundaries.
(3) The similar tendency could be obtained also in SrTiOィイD23ィエD2 bicrystal, which has the same lattice structure and similar electrical properties.
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