2004 Fiscal Year Final Research Report Summary
Development of 3d Transition Metal Oxides with Oxygen p-hole Characters.
| Project/Area Number |
14204070
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
機能・物性・材料
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
TAKANO Mikio Kyoto University, Institute for Chemical Research, Professor, 化学研究所, 教授 (70068138)
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| Co-Investigator(Kenkyū-buntansha) |
TERASHIMA Takahito Kyoto University, Institute for Chemical Research, Associate Professor, 化学研究所, 助教授 (40252506)
AZUMA Masaki Kyoto University, Institute for Chemical Research, Associate Professor, 化学研究所, 助教授 (40273510)
TAKEDA Yasuo Mie University, Faculty of Engineering, Professor, 工学部, 教授 (60093051)
NOHARA Minoru The University of Tokyo, Graduate School of Frontier Sciences, Associate Professor, 大学院・新領域創成科学研究科, 助教授 (70272531)
KUSANO Yoshihiro Kurashiki University of Science and the Arts, College of the Arts, Lecturer, 芸術学部, 講師 (40279039)
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| Project Period (FY) |
2002 – 2004
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| Keywords | high-oxideation state / frustration / soft chemistry / high-pressure synthesis / epitaxial / 3d transition metal / high-temperature superconductors / blue light emission |
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| Research Abstract |
1.Employment of various synthesis techniques : To overcome the difficulty in predicting the structure and the property of crystalline materials due to the many-body problem, we employed various synthesis techniques in searching for new materials. One example is the discovery of superconductivity in (MS)_<1+d>(TaS_2)_2(M=Sn,Pb,Sb,Bi) by intercalation of water molecules and Na ions by means of soft chemistry method. Also, a technique to grow single crystals under high pressure was developed.
2.High-oxidation state effects : Late 3d transition metals (especially those with high oxidations stats such as Fe^<4+/5+/6+>,Co^<4+>,Ni^<3+/4+> and Cu^<2+/3+>) have deep d levels. Delocalized wave functions due to of the high d-p hybridization surpress lattice distortion accompanied by carrier localization. As results, fascinating phenomena such as magnetic frustration expected for systems with high symmetry are realized. SrCo_6O_<11> is a good example.
3.Utilization of anions : We attempted to increase the variation of compounds and dimensional control of physical properties by substituting oxygen ions with other anions having different ionic radius and p levels. One example is a high-T_c superconductor Ca_<2+>Na_xCuO_2Cl_2. An unexpected blue light emission from SrTiO_<3-δ> exhibited that even anion vacancies contribute to the production of new functions
4.Utilization of sub cations : Oxides with Bi^<3+> and Pb^<2+> ions can be regarded as 3d-2p-6s systems because these ions have 6s levels close to O2p level. As results, these sometimes have crystal structures without inversion symmetry. Discoveries of BiCo_3 and PbVO_3 with candidate large electric polarizations and ferromagnetic ferroelectric Bi_2NiMnO_6 are good examples.
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Research Products
(57 results)
