1995 Fiscal Year Final Research Report Summary
Physical Properties in Epitaxial Ferroelectric Films Grown by MBE.
| Project/Area Number |
05402010
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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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 | Kwansei-Gakuin University |
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Principal Investigator |
TERAUCHI Hikaru Kwansei-Gakuin University School of Science, Professor, 理学部, 教授 (00079667)
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| Co-Investigator(Kenkyū-buntansha) |
SANO Naokatsu Kwansei-Gakuin University School of Science, Professor, 理学部, 教授 (00029555)
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| Project Period (FY) |
1993 – 1995
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| Keywords | Molecular Beam Epitaxy / Thin Films / Ferroelectricity / Structural Phase Transition |
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| Research Abstract |
Our main subject of the study is to obtain extremely-thin ferroelectric film epitaxially grown by MBE and to characterize the dielectric constant of the film. The study would clarify the nature of the dipole-dipole interaction in the low-dimensional ferroelectric system.
The thin film of BaTiO_3 was synthesized by MBE methods. The MBE chamber was specially designed for oxygen introduction. Flux of barium and titanium was obtained utilizing the conventional K-cell and the cell using the electron beam heating. Flux was controlled by the computer-controlled shutter. The growth condition of coevaporation and alternate evaporation was found. As a result, it is shown that the flux ratio plays an important role to avoid the degradation of the crystallinity of the thin film and to obtain the film with ideal-stoichiometry.
X-ray diffraction was utilized to characterize the epitaxial film. The information along the growth and in-plane direction was obtained by conventional 2rheta-rheta scans with symmetrical geometry and the grazing incidence geometry. We were able to see the intensity oscillation due to the Laue function, suggesting that the film has extremely uniform thickness. The lattice constant of the film along the in-plane direction suffered fom teh compressive stress, and that along growth direction was elongated, that was usually found in 'pseudomorphic' film.
The ferroelectric properties of the film was measured by the LCR meter. Dielectric constant of the thinner film was degraded as a function of the film thickness. It is predicted that the degraded layrs near the interface existed.
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