1) Tin alloy 
Niobium-tin (Nb3Sn) or triniobium-tin is a metallic chemical compound of niobium (Nb) and tin (Sn), used industrially as a type II superconductor. This intermetallic compound is an A15 phases superconductor. It is more expensive than niobium-titanium (NbTi), but can withstand magnetic field intensity values up to 30 teslas (T), whereas NbTi can wi...