2003 Fiscal Year Final Research Report Summary
Non-collinear magnetism of Transition metal linear clusters
| Project/Area Number |
13640328
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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 |
固体物性Ⅰ(光物性・半導体・誘電体)
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| Research Institution | Shizuoka University |
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Principal Investigator |
FUJIMA Nobuhisa Shizuoka University, Faculty of Engineering, Associated Professor, 工学部, 助教授 (30219042)
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| Co-Investigator(Kenkyū-buntansha) |
ODA Tatsuki Kanazawa University, Faculty of Science, Lecturer, 大学院・自然科学研究科, 講師 (30272941)
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| Project Period (FY) |
2001 – 2003
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| Keywords | Transition-metal cluster / Non-collinear magnetism / Carbon nanotube / First principles molecular dynamics / Density functional method |
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| Research Abstract |
Transition-metal nano materials have been attracting many researchers interests because of their anomalous magnetic properties. In the present project, we have theoretically studied the atomic and magnetic structures of iron nano clusters by using the non-collinear first principles molecular dynamics, and clarified the following points.
(1)Bare Fe chains : In bare Fe linear chains, magnetic alignment changes from collinear to non-collinear (and vice versa) with changing the interatomic distances. It is suggested that the change in the magnetic alignment is caused not only from the antiferromagnetic interaction between 3d electrons but also from RKKY-like interaction between 4s and 3d electrons. In the optimized interatomic distances, a dimerization occurs, especially in chains with even-number atoms, and the magnetic moments align antiparallel in unit of the dimer.
(2)Fe chains in carbon nanocapsules : To stabilize the linear structures, Fe chains are encapsulated in tubal carbon nanotubes terminated by pentagonal rings. A Fe atom in the global capsule is not stable, but Fe chains are stable in tubal capsules, keeping their linear structures. Antiparallel magnetic alignments are dominant in the capsules because of the super exchange interaction between Fe and C atoms.
(3)Iron oxide cluster FenOm : Parallel large magnetic moments appears for n>m, while antiparallel aliments with zero or small net magnetic moments appears for n<m. This is due to the superexchange interaction between Fe and O atoms. The atomic structures and ionization potential of iron oxide anion clusters also investigated for n=1,2 and m=1-6.
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