2004 Fiscal Year Final Research Report Summary
The quantum state and isotope-mixture effects of superabundant vacancies in metals
| Project/Area Number |
13440116
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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 | Chuo University |
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Principal Investigator |
FUKAI Yuh Chuo University, Faculty of Science and Engineering, Professor, 理工学部, 教授 (80055136)
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| Co-Investigator(Kenkyū-buntansha) |
SUGIMOTO Hidehiko Chuo University, Faculty of Science and Engineering, Professor, 理工学部, 教授 (00187668)
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| Project Period (FY) |
2001 – 2004
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| Keywords | Metal-hydrogen system / Vacancy-hydrogen cluster / isotope effect / quantum effect |
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| Research Abstract |
The formation of superabundant vacancy-hydrogen clusters (SAVs) was studied in a number of M-H alloys, and a relation between their equilibrium concentration and hydrogen concentration was established and explained theoretically in terms of entropy effects. The enhancement of metal-atom diffusion caused by SAV formation was elucidated in Nb-H alloys and its overall feature was established over a wide temperature range.
Regarding the quantum state of SAVs, proton NMR signals motionally narrowed at very low temperatures were observed in Nb-H alloys, and attributed to protons executing a cage motion in vacancies via tunneling.
Studies of stress-induced states of hydrogen isotopes in vanadium, by channeling and adiabatic calorimetry, revealed that the site change occurs at higher stresses for D than for H. This provides useful information regarding the nature of H-H (D-D) interactions underlying the stress-induced site change.
A calculation. performed on the scattering of neutrons by quantum-entangled states of protons in solids provided a useful guideline for the interpretation of observed neutron Compton scattering results.
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