Nb3Sn Thin Films and Micro Structure Made by RF Magnetron Sputtering Process with a Nb3Sn Single Target
We have been developing a high field pulsed superconductor with a high elastic modulus fiber for reinforcement. We call the conductor Fiber Reinforced Superconductor (FRS). These fiber reinforced superconductor will be performed by magnetron sputtering techniques of two opposed planar targets in future. In this process for Nb3Sn compound a single material target would be desired to be developed to shorten the deposition process. We have succeeded to make a sputtering target which consists of Nb3Sn single material. The target is made from the reacted Nb3Sn powder of Nb and Sn mixture for composition of Nb3Sn as 3:1. Nb3Sn thin films on MgO substrate were made using this target. The films are crystallized after heat treatment of about 1173 K for 3.6 ks (1 hour). The critical temperature of this film shows about 15.3 K and the size of a equiaxed like grain is about 70 nm. The Nb3Sn film as grown was fabricated on heated substrate. Also the Nb3Sn thin films were made by bronze process. In order to investigate the catalysis of copper in bronze process, further copper thin layer added to this films by sputtering process and then heat treatment has performed to create Nb3Sn. In this case the grain is rather large and looks harder than that of Nb3Sn film with non copper films. Fiber reinforced superconductor of Nb3Sn on Ta fiber has been successfully fabricated with this target. The experimental results in comparison with each other will be shown in this paper.
KeywordsCritical Temperature Copper Film Heated Substrate Grown Film Packing Pressure
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