Tailoring Microstructures of High-Tc Superconducting Films

该项目致力于更好地了解阳离子交换的微观机制和一种新的工艺--PINSE(通过纳米应变工程制造毛孔)。这些工艺为YBa2Cu3O7(YBCO)、Tl基(Tl-HTS)和汞基(Hg-HTS)等几种高温超导体(HTS)的工程微结构和物理性能提供了良好的工程应用前景。将研究三个子主题：1)利用阳离子交换过程外延Hg-HTS薄膜。Tl-HTS和HgHTS之间阳离子交换的可逆性旨在了解通过合金化HgHTS和Tl-HTS并在晶格上添加纳米Pins来改善HgHTS薄膜微结构的阳离子交换机理和应用。2)系统地研究了Tl-HTS和Hg-HTS薄膜的邻近生长，重点研究了Tl-HTS和Hg-HTS薄膜的反相晶界形核，以及Tl-HTS到Hg-HTS薄膜阳离子交换过程中的微观结构演变和变化。通过测量临界电流密度(Jc)作为温度、磁场和磁场取向的函数，具体研究微结构/缺陷和磁钉扎之间的定量关系。3)利用邻域生长和纳米粒子插入的方法制备了YBCO多孔薄膜。这些超导体海绵的JC的显著改善。提出了关于多孔超导体的材料科学和材料物理的问题。为了回答这些问题，将对孔形成机理进行研究，以更好地理解和实现对孔尺寸、密度、形状和分布的精确控制。我们将研究YBCO多孔膜的超导性能，以了解气孔和降维对超导电性的影响。材料科学和材料物理的研究将以连贯的方式进行。我们的目标是获得更好的理解和具有所需微结构和超导性能的高性能YBCO薄膜。*该项目致力于与电子和光子学具有很强技术相关性的基础材料研究，并有效地将研究和教育结合在一起。该项目的影响包括对下一代科学家进行纳米科学和材料科学/物理学方面的教育，并积极重视扩大代表性不足群体的参与。

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.