Development of High Temperature and Rare-Earth Less Superconducting Thin Films by Controlling (Cu, C)-based Artificial Multi-layer Structure

本文对（Cu， C）-1201无稀土超导薄膜的结构成因和实用生长技术进行了研究。1201层顶部和底部的压缩界面应变是产生超导性的主要因素，通过控制在应变外延模式下生长的上下层的厚度来优化超导性。该优化产生了超薄1201层上的超导性。这种层状结构的重复生长是提高单位宽度临界电流密度的一种很有前途的方法。在所有成分共沉积生长的薄膜上也证实了超导性的出现。如上所述，为无稀土超导膜的生长奠定了基础，为实际生长技术奠定了立足点，成功实现了本研究的目的。

The investigation of structural origin and the development of practical growth technique of the (Cu, C)-1201 rare-earth element free, superconducting films have been performed. The compressive interfacial strain at the top and bottom of the 1201 layer is a dominant factor for the emergence of superconductivity, which is optimized by controlling thickness of the over- and under-layers grown in the strained epitaxial-mode. The optimization yields an emergence of superconductivity on the ultra-thin 1201 layer. The repeating growth of this layered structure is a promising method for improving the critical current density per unit width. The emergence of superconductivity has been also confirmed on the films grown by the co-deposition of all of the constituents. As mentioned above, the fundamentals for the growth of the rare-earth free superconducting film and the foothold for practical growth techniques are established, which means the objective of this research is successfully achieved.