| Project/Area Number |
15360353
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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 |
Inorganic materials/Physical properties
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| Research Institution | Meijo University |
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Principal Investigator |
OGAWA Hirotaka Meijo University, Department of Transportation Engineering, Professor, 理工学部, 教授 (20097760)
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| Co-Investigator(Kenkyū-buntansha) |
OHSATO Hitoshi Nagoya Institute of Technology, Department of Materials Science and Engineering, Professor, 材料工学科, 教授 (20024333)
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| Project Period (FY) |
2003 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥15,100,000 (Direct Cost: ¥15,100,000)
Fiscal Year 2005: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 2004: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2003: ¥10,100,000 (Direct Cost: ¥10,100,000)
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| Keywords | Microwave dielectric ceramics / nano-crystal structure analysis / high-Q / Dielectric property / low-dielectric constant material / LTCC / Ceramic / コランダム / 低損失材料 / 低誘電率 / 結晶構造解析 / セラミックス / グリーンフェイス / コランダム系材料 / 高Q材料 / ミリ波 |
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| Research Abstract |
New microwave dielectric ceramics, which have high quality factor and a low dielectric constant, were synthesized and the microwave dielectric property-crystal structure relations in the ceramics were investigated in this project.
In the R_2O_3-AO-MO system (R=rare earth, A=Ba and Sr, M=Cu, Ni and Zn), the R_2AMO_5 ceramics and the solid solutions were prepared by the conventional solid state reaction method. In the case of R_2BaCuO_5 and R_2BaZnO_5 ceramics, the dielectric constants of these ceramics ranged from 11 to 19, depending on the ionic radii of R ions. From the calculation of covalency of cation-oxygen bonds in the crystal structure, it was found that the covalency of R-O bonds decreased with an increase in the ionic radii of R ions and it was suggested that the increase in the dielectric constant was related with the decrease in the covalency of R-O bonds. The Q・f values of R_2AMO_5 ceramics were extremely improved by the Zn substitution for Cu and the highest Q・f value of 190000 GHz was obtained for Y_2BaZnO_5 ceramics. The sintering time dependence of Q・f value on Y_2BaZnO_5 ceramics also revealed that the Q・f value of the ceramics decreased from 190000 to 165000 GHz when the ceramics were sintered for 100h and this result was due to the vaporization of Zn.
In the corundum-structured Mg_4Nb_2O_9 ceramics, the highest Q・f value of 345000 GHz was obtained by the Ta substitution for Nb. However, the Q・f values of the ceramics are drastically decreased by the M' (M'=Ni,Zn and Co) substitution for Mg and from the result of calculation of electric state by first principle method, the differences in the electric state between Mg-O and M'-O may take place the decrease in the Q・f value.
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