1993 Fiscal Year Final Research Report Summary
Disorder characters and fractal structure in the condition plane of two-dimensional superionic conductors
| Project/Area Number |
04452032
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
固体物性
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
HATTORI Takeshi Research Institute for Scientific Measurements, 科学計測研究所, 助教授 (20029234)
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| Co-Investigator(Kenkyū-buntansha) |
YUGAMI Hiroo Research Institute for Scientific Measurements, 科学計測研究所, 助手 (60192803)
ISHIGAME Maruo Research Institute for Scientific Measurements, 科学計測研究所, 教授 (40006143)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Superionic Conductor / Disorder Character / Fractal / Luminescence / Cr^<3+> ion / beta-Alminas / Time-Resolved Spectroscopy / Conduction Plane |
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| Research Abstract |
The instrumentation of a time-resolved luminescence-measurement was constructed by using a multi-channel detector, which was the main equipments. The luminescence from Cr^<3+> ions in Na_<1-x>K_x(Na/K), Na_<1-x>Li_x(Na/Li). Na_<1-x>Ag_x(Na/Ag) and Na_<1-x>Tl_x(Na/Tl) beta-alminas was measured at 15K, and following results were obtained.
1. All decay curves of luminescence can be described by using a combination of two extended-exponential functions, which is characterized by alpha. In this case, a set of three parameters (alpha, tau_1 and tau_2) was used for each sample. Namely, the luminescence have two components which are perturbed from the disordered-conduction plane.
2. alpha depends on the concentration x in Na/K and Na/Ag, in which the mixed-cation(MA) effect was observed, and becomes as minimum at the concentration of the conductivity-minimum. Its minimum-vales obtained will be expected from the percolation theory or fractal strucure. On the other hand, alpha in Na/Tl, in which MA effect was not observed is constant independently of x. Then, it is concluded that alpha is reflected the structure or disordered character of the conduction plane.
3. The coupling constant of the electron-phonon interaction become a maximum at concentration of the conductivity-minimum in Na/Ag.
4. The homogenous linewidth in Na/Ag is the narrowest in the sample of which the conductivity becomes a minimum.
5. The results in 3 and 4 consist of the discussions in 2.
6. It was found from the quasielastic light scattering measurements in Na/Ag that there are two activation energies for ion migration.
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