1999 Fiscal Year Final Research Report Summary
Synthesis and Orbital structure of structure- and valence-controlled layered manganites
| Project/Area Number |
10440107
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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 | Nagoya University |
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Principal Investigator |
MORIMOTO Yutaka Nagoya University, Center for Integrated Research in Science and Engineering, Associated Prof., 理工科学総合研究センター, 助教授 (00283466)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Arao Nagoya University, Center for Intrgrated, 理工科学総合研究センター, 教授 (50159068)
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| Project Period (FY) |
1998 – 1999
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| Keywords | Doped manganites / Structure-control / Valence-control / Orbital physics |
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| Research Abstract |
In the present project, we have systematically synthesized structure- and valence-controlled layered manganites, and have investigated their magnetotransport properties as well a magnetic and crystal structures. In the following, we list a major results obtained in this project.
1. Ground state phase diagram for bilayer manganites
In this system, we can control (a) formal valence of the Mn ions and (b) distortion of the Mn06 octahedra by means of chemical substitution. After a systematical crystal synthesis and measurements of their physical properties, we have experimentally derived the ground state phase diagram for bilayer manganites. We further have found a strong correlation between the magnetic structure and distortion of the Mn06 octahedra.
2. Interrelation between orbital stability and magnetic structure
We have evaluated the orbital stability by calculation of the Madelung potential energy. We clearly have observed strong interrelation between the orbital stability and magnetic structure in the structure-controlled bilayer manganites at a fixed Mn valence (= +3.4). Therefore, in the bilayer manganites, chemical substitution affects the orbital stability. Making a sharp contrast with the other transition metal oxide systems.
3. Direct observation of the orbital (in collaboration with Sakata group)
We recently have succeed in visualizing the orbital state of bilayer manganites by means of MEM, which was developed by Sakata group at Nagoya University. We plan to start a project on this time, that is orbital physics, with getting some research fund.
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