1999 Fiscal Year Final Research Report Summary
Processing of Relaxor Type Ferroelectric Thin Films
| Project/Area Number |
09650756
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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 |
Structural/Functional materials
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| Research Institution | The University of Tokyo |
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Principal Investigator |
ODA Katsuro Institute of Industrial Science, University of Tokyo, Associate Professor, 生産技術研究所, 助教授 (80177229)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Relaxor type ferroelectric / Diffuse phase trasition / Perovskite / Ferroelectricity / (111) oriented |
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| Research Abstract |
A new type of ion beam sputtering machine was installed in order to produce a relaxor type ferroelectric thin film. In this facility, an Ar ions from an Ag ion gun irradiate the metal target and the sputtered radical metal atoms fly toward the substrate. The metal target rotates in plane and can be separated in multiple sections in the rotating direction. The rotating speed can be changed at each segment in order to control the composition of the film. Furthermore, a separate oxygen gun irradiates oxygen atoms/ions on the substrate for the purpose to invoke the oxidation reaction on the substrate in order to produce a high quality oxide film. By coupling the rotating metal target and the oxygen gun, a multicomponent oxide thin film can be produced. By increasing the power of the substrate heater, the temperature of the substrate could be raised up to 500 degree Celsius. When the film was grown at this temperature, a Pb(NbィイD20.5ィエD2FeィイD20.5ィエD2)03 thin film that is completely oriented in the <111> direction is produced. From the AFM images, the films were confirmed to be very dense and square shaped grains with the size of approximately 100nm are aligned. The ferroelectric-paraelectric phase transition is a diffuse type and at the temperature range above the peak temperature of dielectric constant, hysteresis loops are observed. These results confirm that the produced thin film is a relaxor type ferroelectric material. The peak temperature was 100 degree Celsius which is same as for bulk material.
Dielectric dispersion for the bulk Pb (Zr, Ti)0ィイD23ィエD2 ferroelectric materials with various compositions are also investigated in order to derive the compositional dependence mobility of the domain walls quantitatively. Domain wall in the rhomboedral phase turned out to bbe more mobile than in tetragonal phase.
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