On the Synthesis of Metastable A-15 'Nb3Si' by Ion Implantation and on Its Superconducting Trasition Temperature

摘要

The authors have found a new technique for the synthesis of metastable compounds of well defined composition; namely, ion implantation of a selected element into the desired crystal structure. Starting with a substrate material of A-15 Nb3Al0.9Si0.1, two basic approaches were tried towards the formation of A-15 Nb3Si by Si implantation: (1) direct replacement of the Al by Si, and (2) implantation into a surface layer depleted of Al. This later approach proved to be the most successful. It consisted of removing the Al by a diffusion anneal and replacing the Al deficiency by sequential Si implatation. Upon subsequent heat treatment, a surface layer of A-15 Nb3Al0.2Si0.8 was produced. Details of the experimental procedure and a discussion of the superconducting transistion temperature measurements of the implanted surfaces are presented. (Author)