[15a-P7-1~21] 11 Superconductivity（Poster）

[15a-P7-3] Upper critical fields and critical current densities of Nb₃Sn doped with (Ti, Ta) or (Ti, Ga)

〇(M1)Yuya Tanabe¹, Masaru Kiuchi¹, Soji Otabe¹, Teruo Matsushita¹, Yoshiyuki Monju², Taiji Mizuta², Kyoji Tachikawa^3,4, Kozo Osamura⁵ (1.Kyutech, 2.Osaka Alloying Works, 3.NIMS, 4.Tokai Univ., 5.RIAS)

Keywords:Superconductivity, Nb3Sn, Elemental addition effect

It is well known that the small amount of Ti addition to the bronze significantly increases the growth rate of the Nb₃Sn layer and the critical current density J_c characteristic in the high magnetic field. Hence, in order to get the Nb₃Sn having further excellent critical current properties, the addition of Ta or Ga in the bronze with Cu-15Sn-0.3Ti was carried out. The effect on the upper critical field B_c2 and J_c by adding (Ti,Ta) or (Ti,Ga) is discussed.
The samples prepared by the bronze process. The addition of Ta (+0.08mass%) or Ga (+0.5mass%) in the bronze with Cu-15Sn-0.3Ti was carried out. The standard sample which added only Ti was also prepared. Heat treatment of 100 hours or 200 hours at 700 for the diffusion of elements was performed. SQUID magnetometer was used to obtain B_c2 and J_c from hysteresis curve of magnetic moment. It was confirmed by EDX observation that (Ti,Ta) or (Ti,Ga) elements was homogeneously distributed in the Nb₃Sn layer.
In conclusion, the standard sample for 200 hours is the best in the present study. Although a positive effect of (Ti,Ta) and (Ti,Ga) additions is confirmed, the improvement in B_c2 and J_c is limited. It is necessary to find the optimum condition to obtain better performance in addition of fourth elements than the standard sample.