Study on the finite-size effects in ferroelectric thin films and fine-particles

铁电薄膜和细颗粒的有限尺寸效应研究

• 批准号: 09450126
• 负责人: ISHIKAWA Kenji
• 金额: $ 2.11万
• 依托单位: Shizuoka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09450126/
• 关键词: ferroelectrics; thin film; fine-particle; finite size effect; surface relaxation; PbTiOィイD23ィエD2; BaTiOィイD23ィエD2; low temperature growth; 相転移; PZT; レーザアブレーション

Finite size effects on the dielectric properties in ferroelectric materials were studied. Recently, the thickness of ferroelectric films is less than several tens of nanometer. Accordingly, the diameter of the particles in the film may be less than 10 nm. It is known that some dielectric properties differ from that of bulk materials when the size of crystallites approaches nano-meter size. However, the microscopic understanding of the size effect has not been obtained. In this research, we deal with the size effects on the phase transition in several perovskite type ferroelectrics.The first result concerns with the origin of the size effect on the phase transition. The size effects are successfully described by phenomenological theories based on the Landau-Ginzburg equation. The theory assumes the electric polarization near the surface is not uniform and differs from the bulk value. We found that the crystal lattices of lead titanate and barium titanate relaxes towards outside by X-ray measurements with the use of a simple model. We pointed out that the size effect should be caused by the non-homogenous polarization caused by the surface relaxation.We also studied the low-temperature growth of perovskite type ferroelectric films. If we can crystallize the film at low temperatures, we can obtain film composed of very small particles. The phase transition temperatures of such small particle should be lower than that of bulk crystals by the size effect. The dielectric constant of the film is expected to be larger than that of bulk material. We proposed a technique to insert a seeding layer between the film and the substrate. For example, insertion of PbTiOィイD23ィエD2 seeding layer made it possible to obtain a well crystallized film at very low temperature such as 450℃.

对纳米的介电材料的介电特性的有限影响。尚未在垂体钙钛矿类型的铁电型中获得。值。小粒子的颗粒应通过尺寸效应较小的粒子质量。底物。

项目成果

Hisao Suzuki: "Effects of Excess Lead Oxide Addition and Substrates on Crystallization and Electrical Properties of Pb(Zr_<0.53>Ti_<0.47>)O_3 Thin Films from Stable Precursor Sol"Trans. Mater. Res. Soc. Jpn.. Vol.24. 31-34 (1999)

Hisao Suzuki：“过量氧化铅添加和基材对稳定前驱体溶胶中 Pb(Zr_<0.53>Ti_<0.47>)O_3 薄膜的结晶和电性能的影响”Trans。

Hisao Suzuki: "Low Temperature Processing of Pb{(Mg_<1/3>Nb_<2/3>)_<0.9>Ti_<0.1>}O_3 Thin Film by Sol-Gel-Casting"Ferroelectrics. Vol.231. 231-236 (1999)

Hisao Suzuki：“通过溶胶凝胶铸造法低温加工 Pb{(Mg_<1/3>Nb_<2/3>)_<0.9>Ti_<0.1>}O_3 薄膜”铁电体。

Tomio Hirano: "Effect of Seeding Layers on Preparation of PLZT Thin Films by Sol-Gel Method"Kor. J. Ceram.. Vol.5. 50-54 (1999)

Tomio Hirano：“晶种层对溶胶-凝胶法制备 PLZT 薄膜的影响”Kor。

Hisao Suzuki: ""Low-temperature Processing of Pb(ZrィイD20.53ィエD2TiィイD20.47ィエD2)OィイD23ィエD2 Thin Film from Stable Precursor Sol""J. European Ceram. Soc.. Vol. 19. 1397-1401 (1999)

Hisao Suzuki：“来自稳定前体溶胶的 Pb(ZrD20.53D2TiD20.47D2)OiD23D2 薄膜的低温加工”J. 欧洲陶瓷学会 19. 1397-1401 (1999)。

Hisao Suzuki: "Orientation Control of Low-Temperature Processed Pb(Zr,Ti)O_3 Thin Films"Trans. Mater. Res. Soc. Jpn.. Vol.24. 39-42 (1999)

铃木久雄：“低温加工Pb(Zr,Ti)O_3薄膜的取向控制”，Trans。