U.S.-Austria Cooperative Research on Anisotropy In Grain Aligned Superconducting (123)-Compounds

该奖项支持由道格拉斯·K·芬尼莫尔教授领导的爱荷华州立大学物理系科学家与维也纳奥地利大学原子研究所的哈拉尔德·W·韦伯教授及其同事之间的合作互动。这两个小组一直在研究高温超导体的磁性和载流能力的各向异性。他们的目标是开发携带高临界电流的块状超导材料，从而适用于大型磁体的导体材料。它们的合作工作计划在很大程度上依赖于它们互补的专门知识和设施。爱荷华州立大学小组在各向异性超导体理论、颗粒取向材料的样品制备、涡旋线能的测量和涡旋运动的钉扎势的研究方面都非常有经验。奥地利小组在超导体中的辐射损伤方面拥有丰富的经验，并对这些高度各向异性材料的基本磁化性质进行了高度精确的研究。爱荷华州立大学将准备颗粒取向的晶体样品，测量它们的基本性质，并安排它们在美国的几个加速器设施进行照射。奥地利研究小组将使用不同的磁化仪器(包括他们的17特斯拉磁化仪器)测量这些材料的磁性和结构特性。还将使用透射电子光谱学对离子径迹造成的损害进行彻底研究。了解高温超导体中磁通钉扎的各向异性效应具有重要的理论意义和实际意义。与高温材料相比，经典超导体是高度各向同性的，所以这里提出的实验处于一个新的区域，其中维度和拓扑起着更重要的作用。此外，开发新材料和新的加工方法来生产具有更高临界电流密度值的导体也有很大的回报。由于力学性能和输运临界电流较差，目前还没有一种令人满意的磁性导体材料。因此，高温块状超导体临界载流能力的任何提高都将对新磁体和新屏蔽材料的可用性产生重大影响。

This award supports collaborative interactions between scientists in the Department of Physics, Iowa State University, led by Professor Douglas K. Finnemore, and Professor Harald W. Weber and colleagues of the Atomic Institute of the Austrian Universities, in Vienna. The two groups have been studying the anisotropy of the magnetic properties and current carrying capacity of high temperature superconductors. Their goal is to develop bulk superconducting materials which will carry a high critical current and thus be suitable for conductor material in large magnets. Their cooperative work plan relies heavily on their complementary expertise and facilities. The Iowa State University group is very experienced in the theory of anisotropic superconductors, in sample preparation for grain oriented materials, in measure- ments of the vortex line energy and in the study of pinning potentials for vortex motion. The Austrian group has great experience with radiation damage in superconductors and highly accurate studies of the fundamental magnetization properties of these highly anisotropic materials The U.S. group at Iowa State University will prepare the grain oriented crystal samples, measure their basic properties and arrange for their irradiation at several U.S. accelerator facilities. The Austrian group will measure the magnetic and structural properties of these materials using different magnetization instruments (including their 17 tesla magnetiza- tion apparatus.) There will also be a thorough study of the damage done by the ion tracks using transmission electron spectroscopy. The development of an understanding of anisotropy effects for flux pinning in high temperature superconductors would have both fundamental and practical implications. Classical superconductors are highly isotropic compared to the high temperature materials, so the experiments proposed here are in a new regime where dimensionality and topology play a more important role. In addition, there is a large payoff for the development of new materials and new processing methods to produce conductors with higher critical current density values. There is at present no satisfactory conductor material for magnetics because the mechanical properties and the transport critical currents are so poor. Thus, any improvement in the critical current carrying capacity of the high temperature bulk superconductors would have a large impact on the availability of new magnets and new shielding materials.