Study on preparation of Nb3Sn films by bronze route

Abstract

As a promising material, in the field of superconducting radio frequency (SRF), Nb3Sn could be prepared via bronze route, which is fairly mature for preparing the superconducting cable. This paper studies how different annealing temperature and time affect the superconducting properties of Nb3Sn films made by bronze route. Niobium films with μm thickness were deposited on bronze substrates by magnetron sputtering. The prepared samples were annealed at 700 °C and 750 °C for several hours to allow the diffusion of Sn from the bronze substrate to the niobium layer and the formation of the Nb3Sn phase. The obtained films have been characterized via X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy analysis (EDS), and magnetic property measurement system (MPMS). The peaks of the Nb3Sn phase were found by XRD and the EDS result showed the Sn% of the cross-section fluctuates around 23at.%. The average crystallite size is estimated to be about 82 nm. The highest critical temperature of Nb3Sn films prepared by this method is up to 17.6 K.