The observation of tin islands in Nb3Sn thin films deposited by magnetron sputtering

• Published in: Physica. C, Superconductivity Vol. 576; p. 1353667
• Main Authors: Tan, Weiwei, Ma, Rui, Pan, Hui, Zhao, Huijing, He, Xin, Chen, Xiaohuan, Zhao, Cuina, Lu, Xiangyang
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.09.2020; Elsevier BV
• Subjects: Annealing; Critical temperature; Islands; Magnetic fields; Magnetic moments; Magnetron sputtering; Nb3Sn thin film; Niobium; Substrates; Superconducting cavities; Superconductivity; Temperature effects; Thin films; Tin; Titanium nitride; Superconducting cavities; Magnetron sputtering; Nb3Sn thin film
• ISSN: 0921-4534; 1873-2143
• DOI: 10.1016/j.physc.2020.1353667

•Superconducting Nb_3 Sn thin films are obtained by on copper substrate by dc magnetron co-sputtering technique.•The inhomogenous distribution of tin like forming tin island is observed.•The inhomogenous distribution of tin in Nb_3 Sn thin film is analyzed according to EDS and MPMS results. Superconducting Nb3Sn thin films have been produced on copper substrate by dc magnetron co-sputtering technique successfully. XRD and magnetic moment measurement demonstrate the exist of Nb3Sn crystal. By changing the ratio between niobium target sputtering current to tin target, the tin concentration in different films is varied. However, the experiment results indicate critical temperature TC of different Nb3Sn thin film are nearly invariable while the composition of Nb-Sn of those are changed. Highest TC of those films annealing at 650°C are around 12K, while 750°C annealing increase it to 15K. The SEM and element analysis results manifest inhomogenous distribution of tin atoms, where some tin islands appear over the film. The exist of tin-rich areas like tin islands is responsible for such particular performance of Nb3Sn films.