Nb3Ge
Niobium-germanium (Nb3Ge) is an intermetallic chemical compound of niobium (Nb) and germanium (Ge). It has A15 phase structure.
It is a superconductor with a critical temperature of 23.2 K.
Sputtered films have been reported to have an upper critical field of 37 teslas at 4.2 K.[1]