No. 1293
	Microstructures, compositions and physical properties of modern superconducting materials
	Investigating R&D Committee for microstructures, compositions and physical properties of modern superconducting materials
	Keyword : superconductor, microstructure, critical current
	After the discovery of high-Tc cuprate superconductors, understanding of their features were made progress and practical use of cuprate superconducting wire which can be used at higher temperature and higher field than ordinary superconducting wire was started. On the other hand, 40 K-class and 55 K-class superconductivity were achieved for MgB2 in 2001 and iron-based superconductors in 2008, respectively. These compounds are potential candidates of next generation practical materials. Properties of conventional metallic superconductors, such as Nb-Ti and Nb3Sn, have been continuously improved even after 50 years of their discoveries. Based on these backgrounds, this special investigative committee investigated microstructures, compositions and physical properties of modern superconducting materials. During 3 years understanding of relationship between microstructures and critical currents were advanced, and control of chemical compositions are used not only basic research but also to improve properties of superconducting wires. In this report we summarized recent progress of superconducting materials and factors to determine their physical properties.
	©2007. The Institute of Electrical Engineers of Japan