Most of high Tc A–15 type Nb3Ge samples (Tc=23∼24 K) synthesized by us using CVD method contained a large quantity of the tetragonal Nb5Ge3 phase. These high Tc samples were unstable against thermal cycles and Tc's decreased down to ∼20 K. The coexisting Nb5Ge3 phase must play important roles to keep the high Tc state of Nb3Ge phase by stabilizing the A–15 type crystal structure and also to raise the magnetic flux pinning force density as pinning centers. It is suggested that the appearance of an anharmonic type potential acting on Nb atoms is closely related with high Tc of Nb3Ge phase.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.