[19a-C31-1~6] 11.1 Fundamental properties

9:45 AM - 10:00 AM JST(12:45 AM - 1:00 AM UTC)

[19a-C31-4] Phase stable region and superconducting properties of RE247(RE = Nd, Gd)

〇Tetsuya Matsushita¹, Haruto Niitu¹, Takanori Motoki¹, Jun-ichi Shimoyama¹ (1.Aoyama Gakuin Univ.)

Keywords:

superconductivity

RE247 has an alternating stacked structure of RE123 and RE124, and has a narrow formation conditions between RE123 and RE124 under high temperature and high oxygen partial pressure. RE247 is also known as a high T_c material, and Y247 has been reported to show T_c approximately 95 K, which is higher than the T_c of Y123 (92 K). However, T_c tends to decrease as the ionic radius of RE³⁺ increases due to RE/Ba solid solution for samples sintered at high temperatures and high oxygen partial pressures. In this study, I aim to suppress RE/Ba solid solution and fabricate RE247 that shows a high T_c above 100 K under various sintering and post annealing conditions. In my previous study, I found that Y247 has a phase stable region in air and O₂ flow, which is outside the phase formation zone. Especially in O₂ flow, Y247 was found to be stable even after post annealing at temperatures higher than 900°C