Study of space charge and local lattice distortion in ionic conductors by artificially synthesized superlattice structures in nanometer-scale

人工合成纳米级超晶格结构研究离子导体中的空间电荷和局域晶格畸变

• 批准号: 16074202
• 负责人: SATA Noriko
• 金额: $ 6.08万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research on Priority Areas
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16074202/
• 关键词: superlattice; MBE, epitaxial; interfacial properties; fuel cells; lattice defects; 人工格子; プロトン導電体; パルスレーザデポジション; ドーパント; 薄膜; 超格子; ナノ材料; PLD; ペロブスカイト型酸化物

In this study, artificial layers are synthesized to tune dopant distribution in proton-conducting perovskite-type oxides in order to investigate influence of the dopant distribution on proton dynamics. SrZrO3 doped with trivalent rare earth metal has been chosen as a model material, as its properties of bulk crystal is well known. In this type of proton conductors, it is suggested that the dopant might have a significant effect on the proton dynamics.The artificial layers, in which the dopant is distributed periodically in two-dimensional plane, are formed by Pulsed Laser Deposition (PLD). The host material, SrZrO3 (SZO) and the dopant layer, Y2O3 are alternately deposited on (001)MgO substrate. The thickness of SZO and Y2O3 layers are 5-20 and 0.25-1nm, respectively, and the total thickness of the film is about 200nm. HREM cross sectional views of the thin films show that very thin and flat interfacial layers of Y2O3 are formed and there is almost no difference in atomic arrangements … More between SZO and Y2O3 in HREM image, though their structure in bulk crystals are different. XRD analysis revealed that the SZO lattice is slightly distorted due to a large difference in thermal expansion coefficient. The epitaxial relationship of the artificial layer and the MgO substrate is (001)//(001) and [100]//[100].In-plane electrical conductivity in wet air saturated with H2O and D2O at 20℃ has been obtained by impedance spectroscopy. An isotope effect is observed and it is confirmed that the main carrier in the artificial layers is proton below 400℃. It is found that the conductivity is the highest and the activation energy is the lowest when the SZO layer thickness is about 10nm. This result suggests that there is a preferable arrangement of the dopant distribution in this material, however, the conductivity was much low and the activation energy was high compared to those of bulk crystals. The electronic structures around the band gap of artificial layers are the same irrespective of the layer structure and are different from those of SZO and SZY thin films. Different mechanisms of proton conduction must be considered to elucidate the results for the artificial layers. Studies by hetero-layered structures of proton conductors might give important information to solve the problem of very low conductivity at the grain boundary region in their bulk crystals. Less

本研究通过合成人工层来调节质子导电钙钛矿型氧化物中掺杂剂的分布，以研究掺杂剂分布对质子动力学的影响。我们选择掺三价稀土的SrZrO3作为模型材料，因为它的块状晶体性质是众所周知的。在这类质子导体中，掺杂剂可能对质子动力学有显著影响。采用脉冲激光沉积（PLD）技术制备了掺杂物在二维平面上周期性分布的人工层。载体材料SrZrO3 （SZO）和掺杂层Y2O3交替沉积在（001）MgO衬底上。SZO和Y2O3层的厚度分别为5-20 nm和0.25-1nm，膜的总厚度约为200nm。薄膜的HREM横截面图显示，SZO和Y2O3形成了非常薄而平坦的界面层，在HREM图像中原子排列几乎没有差异，尽管它们在体晶中的结构不同。XRD分析表明，由于热膨胀系数差异较大，SZO晶格有轻微畸变。人工层与MgO衬底的外延关系为(001)//(001)和[100]//[100]。用阻抗谱法测定了20℃时饱和水和D2O湿空气的平面内电导率。观察到同位素效应，证实了400℃以下人工层的主要载流子是质子。发现当SZO层厚度约为10nm时，其电导率最高，活化能最低。结果表明，该材料具有较好的掺杂分布规律，但其电导率较低，活化能较高。人工层带隙周围的电子结构与SZO和SZY薄膜不同，与层结构无关。为了解释人工层的结果，必须考虑不同的质子传导机制。对质子导体异质层状结构的研究可能为解决质子导体体晶体晶界区电导率极低的问题提供重要信息。少

项目成果

Oxygen permeation properties and the stability of La0.6Sr0.4Fe0.8Co0.2O3 studied by Raman spectroscopy

• DOI: 10.1016/j.ssi.2006.07.025
• 发表时间: 2006-10
• 期刊: Solid State Ionics
• 影响因子: 3.2
• 作者: F. Iguchi;N. Sata;H. Yugami;H. Takamura

Reflection spectra of mixed-cation β-aluminas in ultraviolet and vacuum-ultraviolet regions

混合阳离子β-氧化铝在紫外和真空紫外区的反射光谱

• 发表时间: 2004
• 期刊: Solid State Ionics 175
• 作者: T.Higuchi;T.Tsukamoto;N.Sata;S.Yamaguchi;S.Shin;T.Hattori;Takeshi Hattori
• 通讯作者: Takeshi Hattori

The influence of grain structures on the electrical conductivity of a BaZr0.95Y0.05O3 proton conductor

• DOI: 10.1016/j.ssi.2006.07.008
• 发表时间: 2006-10
• 期刊: Solid State Ionics
• 影响因子: 3.2
• 作者: F. Iguchi;Takehisa Yamada;N. Sata;T. Tsurui;H. Yugami

Structural and electrical properties of SrZr0.95Y0.05O3/SrTiO3 superlattices

• DOI: 10.1016/j.ssi.2006.05.043
• 发表时间: 2006-10-31
• 期刊: SOLID STATE IONICS
• 影响因子: 3.2
• 作者: Kuwata, Naoaki;Sata, Noriko;Yugami, Hiroo
• 通讯作者: Yugami, Hiroo

Synthesis of Hetero-Interface of Proton Conducting Oxides

质子传导氧化物异质界面的合成

• 发表时间: 2007
• 作者: T.Higuchi;T.Tsukamoto;N.Sata;S.Yamaguchi;S.Shin;T.Hattori;Takeshi Hattori;T.Higuchi;Junichi Kawamura;Noriko SATA;Noriko Sata;Noriko Sata
• 通讯作者: Noriko Sata