2007 Fiscal Year Final Research Report Summary
Search for novel highly-correlated oxides without perovskite-type structures using hydrothermal synthesis and measurements of their electronic properties at low temperature
| Project/Area Number |
17540341
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Condensed matter physics II
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| Research Institution | Chuo University |
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Principal Investigator |
SATO Hirohiko Chuo University, Faculty of Science and Engineering, Associate Professor (90262261)
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| Project Period (FY) |
2005 – 2007
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| Keywords | transition metal oxides / highly correlated system / hydrothermal synthesis / crystal structure / magnetism / electric conduction / low temperature |
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| Research Abstract |
Transition metal oxides are interesting system for their variety of electronic properties such as ferromagnetism, superconductivity and giant magnetoresistance. These discoveries are very important not only for its applications but also from a fundamental point of view of solid-stabs physics. In our country, most of studies of transition metal oxides have been, so far, concentrated on perovskite-type compounds. For further advance in this field, it is also important to discover more and more new transition metal oxides including non-perovsltite type compounds. hi this project, I succeeded to synthesize several new transition metal oxides without pemvskite structure using hydrothermal technique. The detailed results are as Mows.
1. Novel hollandite type transition metal oxides.
We discovered new hollandite type transition metal oxides, Rb_<15>Mo_8O_<16>, K_2Rh_8O_<16> and Rb_<12>Rh_8O_<16>. Measurements of the magnetization and the conductivity revealed that the electrons are localized on Mo4 clusters in the Mo-hollandite, whereas the Rh-hollandites have characteristics of highly correlated metal
2. Anomalous coexistence of metallic conduction and spin glass magnetism in a novel pyrochlore ruthenate.
We discovered a novel ruthenium pyrochlore Ca_2Ru_2O_7. The magnetic susceptibility reveals that Pauli paramagnetism and Curie-Weiss type paramagnetism. Furthermore, the localized spins undergo spin glass transition at low temperature.
3. Anomalous magnetism in new iron boroxide.
We succeeded to synthesize a new iron boroxide Fe3_B_7O_<13>(OH) for the first time. Measurements of the magnetization revealed that this compound undergoes successive magnetic phase transition at low temperature. The magnetic phases are strongly dependent on the orientation of magnetic fiekl.
4. Various magnetic phases in lithium ruthenates.
We synthesized several Li-Ru-O ternary compounds and discovered various interesting magnetic phases such as spin glass.
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[Presentation] Temperature dependence of electronic structure in orbital fern magnetism of CoMnO_32006
Author(s)
Masaichiro, Mizumaki, Naomi, Kawamura, Takayuki, Uozumi, Hirohiko, Sato, Tetsuya, Nakamura, Masayoshi, Ito, Yoshiharu, Sakurai
Organizer
2006 autumn meeting Physical Society of Japan
Place of Presentation
at Chiba Univ
Year and Date
2006-09-23
Description
「研究成果報告書概要(欧文)」より
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