1999 Fiscal Year Final Research Report Summary
Vacancy Waves in a Quantum Solid ィイD13ィエD1He
| Project/Area Number |
08240218
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Research Institution | Nagoya University |
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Principal Investigator |
MAMIYA Takayoshi Graduate School of Science, Nagoya University, Professor, 大学院・理学研究科, 教授 (20022600)
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| Co-Investigator(Kenkyū-buntansha) |
NAGAOKA Yousuke Kansai University Professor, 工学部, 教授 (60022539)
MATSUSHITA Taku Graduate School of Science, Nagoya University, Assistant Professor, 大学院・理学研究科, 助手 (00283458)
MIURA Yuichi Graduate School of Science, Nagoya University, Associate Professor, 大学院・理学研究科, 助教授 (30175608)
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| Project Period (FY) |
1996 – 1998
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| Keywords | Quantum Solid / Spin Polaron / Depressurized Solid / Tunnel Effect / Dislocation / Zero Point Vacancy Wave / Solid Helium / Amorphous Solid |
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| Research Abstract |
We aim at verifying that the vacancies move as vacancy waves because of tunneling of ィイD13ィエD1He atoms in solid ィイD13ィエD1He. We studied the vacancy waves in three categories. (1) specific heat, (2) motion of dislocation and (3) zero point vacancy wave. (1) A spin polaron is a region where ィイD13ィエD1He spins are aligned ferromagnetically around a vacancy. We have observed an excess specific heat over the specific heat due to the exchange interaction. We checked whether it arises from spin polarons due to vacancies by applying a strong magnetic field. The results show that the excess specific heat does not arise from spin polarons but the amorphous solid ィイD13ィエD1He layers on the substrate. (2) We studied the motion of dislocations in solid ィイD13ィエD1He by the torsional oscillator technique. We studied the temperature dependence of the critical strain amplitude where the dissipation starts to increase.
We have obtained clear evidence of the crossover from thermal to quantum tunneling of the dislocations through the Peierls potential. (3) We have been performing the experiment of pulsed NMR for depressurized solid in the fields of 8-15T. We aim at observing a decrease in TィイD21ィエD2 and increases in TィイD22ィエD2 and the diffusion constant due to the appearance of zero-point vacancy waves. So far, we have not yet confirmed the presence of zero-point vacancy waves.
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