NSF/ONR: In-Plane Aligned Buffer-Layer Interfaces for High Temperature Superconductors

小行星9421911 本研究为期三年，主要研究高温氧化物超导薄膜在多晶和非晶衬底上的生长，旨在进一步了解高温氧化物超导薄膜Y-Ba-Cu-O和Tl-Ba-Ca-Cu-O（1223相）中a-b面的双轴取向及其成核和生长机制。两种方法，离子束辅助沉积和图形外延生长，将用于制造集成的薄膜缓冲层衬底复合系统。 该项目的最终目标是开发和优化工艺技术，用于在金属和玻璃基板上使用离子束辅助沉积制造具有高临界电流密度的长HTS薄膜。 最初，双轴对准的钇稳定的氧化锆（YSZ）缓冲层将沉积在哈氏合金。 的YSZ膜的取向，然后将研究作为离子束的角度，离子/原子流量比，离子束能量和腔室压力的函数。 离子束辅助沉积对对准和蚀刻的影响将被调查：和扫描和透射电子显微镜将被用来建立沉积条件和膜生长机制之间的关系。 还将采用图形外延法在哈氏合金上制备双轴取向的高温超导薄膜。 由于临界长度是双轴取向的关键参数，临界长度与界面剪切强度、表面膜厚度和断裂强度之间的关系也将得到解决。 将结果与理论预测进行比较。 从这项工作中得到的晶体生长和取向的改善，预计将显着提高高温超导薄膜的电和磁性能。 此外，通过更好地了解物理过程和优化沉积参数，这项工作应该促进实际应用的发展。 多年前高温超导体的发现，由于电力传输效率的巨大提高，有望在电机和电子设备中获得重大的商业应用。 然而，这一进展受到两个特点的阻碍：（1）超导温度仍然远低于室温;（2）实际设备的加工仍然相对缓慢，其对性能的影响尚未完全了解。 这项研究提供了一个机会，使该技术更接近超导体的大规模商业化。 ***

9421911 Shaw This three-year study of high temperature oxide superconductor (HTS) thin-film growth on polycrystalline and amorphous substrates will further understanding of the biaxial alignment of a-b planes and the related nucleation and growth mechanisms in two HTS thin films, Y-Ba-Cu-O and Tl-Ba-Ca-Cu-O (1223 phase), selected for this study. Two methods, ion-beam assisted deposition and graphoepitaxial growth, will be used to fabricate integrated film-buffer-substrate composite systems. The ultimate goal of this project is to develop and optimize processing techniques for the fabrication of long HTS thin films with high critical current densities on both metallic and glass substrates using ion-beam assisted deposition. Initially, biaxially aligned buffer layers of yttrium-stabilized zirconia (YSZ) will be deposited on Hastelloy. The orientation of the YSZ film will then be studied as a function of ion-beam angle, ion/atom flux ratio, ion-beam energy and chamber pressure. The effect of ion-beam assisted deposition on alignment and etching will be investigated: and scanning and transmission electron microscopy will be used to establish the relationship between the deposition conditions and the film-growth mechanism. Graphoepitaxial methods will also be employed to produce biaxially aligned HTS films on Hastelloy. As critical length is a crucial parameter of biaxial alignment, the relationship between critical length and interfacial shear strength, surface film thickness, and fracture strength will also be addressed. Results will be compared to theoretical prediction. Improvements in crystalline growth and alignment resulting from this work are expected to significantly improve the electric and magnetic properties of high temperature superconductor thin films. Further, by gaining better insight into the physical processes and by optimizing the deposition parameters, this work should foster the development of practical applications. Discovery of high temperature superconductors years ago promised major commercial applications in electrical machineries and electronic devices due to enormous increase in the efficiency of transmission of electricity. However, progress has been hampered by two features: (1) superconducting temperatures are still well below room temperature and (2) processing of practical devices remain relatively slow and its impact on properties are not fully understood. This research offers the opportunity to bring the technology a little closer to larger scale commercialization of superconductors. ***