PREPARATION METHOD AND RF BEHAVIOR OF NB3SN THIN-FILMS OBTAINED BY BRONZE PROCESS

Aiming to application in r.f. devices, a method to obtain Nb3Sn thin f ilms, combining sputtering technique and bronze process, has been deve loped. A niobium film, 300-500 nm thick, is deposited by sputtering on to a 7 at, % tin bronze substratum, In order to allow the diffusion of tin into niobium and the formation of the A15 phase, the sample is ma intained at about 700 degrees C during the deposition, and for several hours after the deposition. A Nb3Sn film with very good adhesion on t he substratum has been obtained. The rf behaviour of film has been ana lyzed at about 10 GHz at temperature near Tc, using a host copper cavi ty having the tap plate substituted with the bronze-Nb3Sn sample. Both the quality factor and the frequency shift have been measured.