1999 Fiscal Year Final Research Report Summary
Origin of fundamental functions in relaxor ferroelectrics
| Project/Area Number |
09440122
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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Ⅰ(光物性・半導体・誘電体)
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| Research Institution | Waseda University |
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Principal Investigator |
UESU Yoshiaki Waseda University, School of Science and Engineering, Professor, 理工学部, 教授 (10063744)
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| Co-Investigator(Kenkyū-buntansha) |
YAMADA Yasusada Adavanced Research, Institute of Science & Engineering, 理工学総合研究センター, 教授 (00028101)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Relaxon / ferroelectrics / Pb (Mg 1 / 3 N6 2 / 3) O_3 / Phase Transition / Long namgeorden / Time-depandent Gingliurg-Landan Equation / Nentron Scattering / binefringence |
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| Research Abstract |
Relaxors ferroelectrics exhibit broad and huge dielectric susceptibility and the biggest piezoelectric response and are promising materials for small-size capacitors with large capacitance, actuators and ultra-sonic devices. However, the origin of their colossal dielectric response is not well understood, although various models have been proposed so far. In particular, in some prototype relaxors such as Pb (Mg1/3Nb2/3)O3, the long-range order is not developed down to liquid helium temperature. We think that this phenomenon is essential for relaxor properties and have investigated by means of optical, nonlinear optical and neutron scattering techniques. Our previous study revealed that the long-range order can be induced under the applied electric field but shows quite different paths if the specimen experiences different pre-history. The present study clarified that the long-range order develops after long incubation time, which overpasses several ten hours in low temperature. The relaxation processes are found to be classified by at least two processes : One is rather fast response which obeys the Debye-type law and the other is the long process which can be normalized if we introduced an onset time. We are now analyzing these data introducing the elastic long-range interaction force into the Ginzburg-Landau equation.
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