Mechanical doping of strontium titanate

钛酸锶的机械掺杂

• 批准号: 398795637
• 负责人: Professor Dr.-Ing. Jürgen Rödel
• 金额: --
• 依托单位: Fachgebiet Nichtmetallisch-Anorganische Werkstoffe
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/398795637?language=en
• 关键词: Mechanical; doping; strontium; titanate

The goal of this proposal lies in a scientific elucidation of the influence of dislocations on the electrical conductivity of strontium titanate (SrTiO3). It is known, that dislocation cores in this material have a very high density of oxygen vacancies and are therefore positively charged. A compensating charge zone around the dislocations is negatively charged. The dislocations thereby strongly alter the defect equilibrium in the sample. Dislocations are to be introduced in blocks of SrTiO3 at room temperature and intermediate temperature by plastic deformation. Then the electrical properties are to be determined by impedance spectroscopy globally as well as locally at well-defined dislocation structures. Before plastic deformation the starting defect concentration can be modified by either acceptor-doping, donor-doping or tempering in reduced atmosphere. Similarly, the dislocation structure can be modified after plastic deformation by temperature and electric field treatment. Oxygen transport is to be quantified by secondary mass spectroscopy. A high resolution multi-scale characterization of the dislocation network and its dynamics is envisaged using dark-field X-ray microscopy in collaboration with the DTU in Denmark at a beamline at the ESRF. This affords imaging singular dislocations and their transformation under mechanical load, electric field and temperature. Commercial SrTiO3 single crystals as well as specially manufactured SrTiO3 single crystals with low dislocation density will be utilized. The latter provides the advantage to have a large effect of dislocation density through plastic deformation. Preliminary work provided plastic deformation of SrTiO3 single crystals as well as determination of the density of dislocations by rocking curve quantification and by determining etch pits.

本提案的目的在于科学地阐明位错对钛酸锶（SrTiO3）电导率的影响。众所周知，这种材料中的位错核具有非常高密度的氧空位，因此带正电。位错周围的补偿电荷带负电荷。位错因此强烈地改变了样品中的缺陷平衡。在室温和中温条件下，SrTiO3块体通过塑性变形产生位错。然后用阻抗谱法在全局和局部明确的位错结构上确定电学性质。在塑性变形前，可以采用受体掺杂、供体掺杂或还原气氛回火的方法来修正起始缺陷浓度。同样，通过温度和电场处理，塑性变形后的位错结构也可以得到修正。氧输运要用二次质谱法定量。与丹麦DTU合作，在ESRF的光束线上，设想使用暗场x射线显微镜对位错网络及其动力学进行高分辨率多尺度表征。这提供了成像奇异位错及其在机械载荷，电场和温度下的转变。将利用商业SrTiO3单晶和专门制造的低位错密度SrTiO3单晶。后者的优点是通过塑性变形对位错密度产生较大的影响。初步工作提供了SrTiO3单晶的塑性变形，并通过摇摆曲线量化和蚀刻坑测定了位错密度。

项目成果

Conceptual Framework for Dislocation-Modified Conductivity in Oxide Ceramics Deconvoluting Mesoscopic Structure, Core, and Space Charge Exemplified for SrTiO3.

• DOI: 10.1021/acsnano.0c04491
• 发表时间: 2020-11
• 期刊: ACS nano
• 影响因子: 17.1
• 作者: L. Porz;T. Frömling;A. Nakamura;Ning Li;Ryohei Maruyama;K. Matsunaga;P. Gao;H. Simons;C. Dietz-C

High temperature creep‐mediated functionality in polycrystalline barium titanate

• DOI: 10.1111/jace.16881
• 发表时间: 2019-11
• 期刊: Journal of the American Ceramic Society
• 影响因子: 3.9
• 作者: Pengrong Ren;Marion Höfling;J. Koruza;S. Lauterbach;Xijie Jiang;T. Frömling;D. Khatua;C. Dietz;L. Porz;R. Ranjan;H. Kleebe;J. Rödel

Bridging the Gap between Bulk Compression and Indentation Test on Room-Temperature Plasticity in Oxides: Case Study on SrTiO3

• DOI: 10.3390/cryst10100933
• 发表时间: 2020-10-01
• 期刊: CRYSTALS
• 影响因子: 2.7
• 作者: Fang, Xufei;Porz, Lukas;Nakamura, Atsutomo
• 通讯作者: Nakamura, Atsutomo

Donor and acceptor-like self-doping by mechanically induced dislocations in bulk TiO2

• DOI: 10.1016/j.nanoen.2021.105944
• 发表时间: 2021-03-13
• 期刊: NANO ENERGY
• 影响因子: 17.6
• 作者: Muhammad, Qaisar Khushi;Porz, Lukas;Froemling, Till
• 通讯作者: Froemling, Till

Dislocation-toughened ceramics.

• DOI: 10.1039/d0mh02033h
• 发表时间: 2021-05
• 期刊: Materials horizons
• 影响因子: 13.3
• 作者: L. Porz;Arne J. Klomp;X. Fang;Ning Li;C. Yildirim;C. Detlefs;E. Bruder;Marion Höfling;W. Rheinheimer;E. Patterson;P. Gao;K. Durst;A. Nakamura;K. Albe;H. Simons;J. Rödel