2004 Fiscal Year Final Research Report Summary
A study on dynamical charge fluctuation and lattice dynamics of metal oxcides by X-ray inelastic scattering
| Project/Area Number |
14340105
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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 (2003-2004)
Kyoto University (2002) |
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Principal Investigator |
YAMADA Kazuyoshi Tohoku University, Institute for Materials Research, Professor, 金属材料研究所, 教授 (70133923)
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| Co-Investigator(Kenkyū-buntansha) |
OHOYAMA Kenji Tohoku University, Institute for Materials Research, Associate Professor, 金属材料研究所, 助教授 (60241569)
FUJITA Masaki Tohoku University, Institute for Materials Research, Research Associate, 金属材料研究所, 助手 (20303894)
MIZUKI Junichiro Japan Atomic Energy Research Institute, Synchrotron Radiation Research Center, Director, 放射光科学研究センター, 次長(研究職) (90354977)
ISAWA Kazuyoshi Tohoku Electric Power Co.,Inc., Research and Development Center, Researcher, 研究開発センター, 研究員
HIRAKA Haruhiro Tohoku University, Institute for Materials Research, Research Associate, 金属材料研究所, 助手 (90323097)
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| Project Period (FY) |
2002 – 2004
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| Keywords | High-Tc superconductivity / electron-lattice interaction / lattice vibration / X-ray inelastic scattering / synchrotron radiation / neutron scattering |
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| Research Abstract |
The purpose of this project is to perform a systematic study on the interplay between dynamics of charge, spin and lattice in metal oxides with strongly correlated electrons.
One experimental uniqueness of this project is a complementary use of both X-ray inelastic scattering and neutron scattering techniques. Another uniqueness is to use both large single crystals and concentration-graded crystals. Particularly, the latter crystals are firstly utilized to the comprehensive spectroscopic studies by X-ray inelastic scattering in this project. Theses experimental uniqueness contributed a lot to obtain the new results which are shown below.
(I)In a wide doping region, we succeeded in growing concentration-graded crystals of Sr doped La_<2-x>Sr_xrCuO_4 with x extending from 0.00 to 0.30. By using a scanning SQUID magnetometer we also succeeded in observing a boundary between the semiconducting-superconducting phases in real space as a boundary of vortex states below the transition temperature.
(II)By using a synchrotron X-ray beam with high luminosity and by emitting the beam spot onto the different positions on the concentration-graded crystal we could obtain the information of lattice dynamics as a function of doping concentration in a wide doping region for the first time. One of the important discoveries is the anomalous softening of the Cu-O bond stretching mode only seen in the superconducting region where the life-time of phonons is also anomalously short. These anomalies suggest the strong electron-phonon coupling in the superconducting doping region and provide us important information on the role of electron-phonon coupling in this system for the paring mechanism.
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