Tailoring Microstructures of High-Tc Superconducting Films

该项目致力于更好地理解阳离子交换的微观机制和一种新的工艺，PONSE（孔隙纳米应变工程）。这些工艺为包括YBa2Cu3O7 （YBCO）、tl基（Tl-HTS）和hg基（Hg-HTS）超导体在内的几种高tc超导体（HTS）薄膜的工程微观结构和物理性能提供了希望。本文将研究三个子课题：1)利用阳离子交换工艺制备Hg- HTS薄膜的外延。研究Tl-HTS与ht - hts之间阳离子交换的可逆性，旨在了解阳离子交换机理，并应用于通过在晶格上添加纳米针脚和合金来改善ht - hts薄膜微观结构的工艺。2)系统研究了Tl-HTS和Hg-HTS薄膜的相邻生长，重点研究了Tl-HTS到Hg-HTS薄膜阳离子交换过程中通过反相晶界形成成核、微观结构演变和微观结构变化。通过测量临界电流密度（Jc）作为温度、磁场和磁场方向的函数，将研究微观结构/缺陷与磁钉钉之间的定量关联。3)通过邻近生长和纳米颗粒插入，通过PONSE工艺获得多孔YBCO膜的研究。Jc的显著改善。超导体的海绵。提出了多孔超导体的材料科学和材料物理问题。为了回答这些问题，将对孔隙形成机制进行研究，以便更好地理解和实现对孔隙尺寸、密度、形状和分布的精确控制。研究多孔YBCO薄膜的超导性能，以了解孔隙和降维对超导性的影响。材料科学和材料物理的研究将以连贯的方式进行。目标是获得更好的理解和高性能的YBCO薄膜，具有理想的微结构和超导性能。***本项目开展与电子、光子学技术相关性强的基础材料研究，实现科研与教育的有效结合。该项目的影响包括教育纳米科学和材料科学/物理学的下一代科学家，积极的PI强调扩大代表性不足的群体的参与。

This project strives for greater understanding of microscopic mechanisms of cation exchange and a new process, PONSE (Pores by nanoscale strain engineering). These processes hold promise for engineering microstructures and physical properties of several high-Tc superconductor (HTS) films including YBa2Cu3O7 (YBCO), Tl-based (Tl-HTS) and Hg-based (Hg-HTS) superconductors. Three sub-topics will be investigated: 1) epitaxy of Hg- HTS films using the cation exchange process. The reversibility of cation exchange between Tl-HTSs and Hg-HTSs is aimed at understanding the cation exchange mechanism and application of the process for improving microstructures of Hg-HTS films via alloying Hg-HTS and Tl-HTS and adding nano-pins on the lattice. 2) systematic study of vicinal growth of Tl-HTS and Hg-HTS films, with focus on nucleation via anti-phase grain boundary formation, microstructure evolution and microstructure variation during cation exchange from Tl-HTS to Hg-HTS films. A quantitative correlation between microstructure/defects and magnetic pinning will be investigated specifically through measurement of critical current density (Jc) as function of temperature, magnetic field and the orientation of the magnetic field. 3) studies of porous YBCO films obtained via the PONSE process through vicinal growth and nanoparticle insertion. The significant improvement in the Jc of these .superconductor sponges. raises questions on both material science and material physics of the porous superconductors. To answer these questions, the mechanism of pore formation will be investigated for greater understanding and achievement of precise control of pore dimension, density, shape and distribution. The superconducting properties of the porous YBCO films will be studied to understand the role of pores and reduced dimension on superconductivity. The studies of material science and material physics will be carried out in a coherent fashion. The goal is to achieve greater understanding and high performance YBCO films with desired microstructures and superconducting properties. *** The project addresses fundamental materials research with strong technological relevance to electronics and photonics, and effectively integrates research and education. The impact of the project includes education of the next generation of scientists in nanoscience and material science/physics with active PI emphasis on broadening participation of underrepresented groups.