| Project/Area Number |
09440128
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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 |
固体物性Ⅱ(磁性・金属・低温)
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| Research Institution | Tohoku University |
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Principal Investigator |
ENDOH Yasuo Tohoku University, Department of Physics, Professor, 大学院・理学研究科, 教授 (00013483)
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| Co-Investigator(Kenkyū-buntansha) |
SATO Nariaki Tohoku University, Department of Physics, Research Physicist, 大学院・理学研究科, 助手 (30170773)
YAMADA Kazuyoshi Kyoto University, Institute for Chemical Research, Professor, 科学研究所, 教授 (70133923)
HIROTA Kazuma Tohoku University, Department of Physics, Assistant Professor, 大学院・理学研究科, 助教授 (90272012)
MIZUKI Junichiro Tohoku University, Department of Physics, Professor, 大学院・理学研究科, 教授
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| Project Period (FY) |
1997 – 1998
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| Keywords | orbital ordering / x-ray magnetic scattering / ATS scattering / Jahn Teller effect / synchrotron radiation / manganites / neutron scattering / lift of orbital |
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| Research Abstract |
We have studied the "high temperature superconductivity " and /or "colossal magnetoresistance (CMR)" as the key phenomena in the strongly correlated electron systems. In order to explore this important issue, we initiated to investigate a novel degree of freedom of "order" by using new technique of the synchrotron x-ray scattering besides neutron scattering.
First we studied carefully the mechanism of the resonant x-ray scattering of the orbital order occurred at the energy of K edge of the magnetic metal element, actually Mn cations. Then we found the mechanism that the intra Coulomb interaction between 4p and 3d orbital which is in the orbital ordered state lifts the 4p degeneracy. Then it gives rise an enhancement or resonance. Then we deeply studied the orbital order in LaMnO_3 originated by the Jahn Teller effect by using this newly established technique of the synchrotron x-ray scattering.
Second, we also extend this technique to study the phase transition of metal insulator in the doped manganites as recognized the CMR materials. We found that the phase transition is triggered by the orbital order-disorder transition.
Third, we extend this project studied during the recent two years granted to a new project aiming the standard probe of studying the orbital fluctuations.
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