The effects of interstitial oxygen on superconducting electronic phases in strontium and oxygen co-doped La1.937Sr0.063CuO4+δ

• 来源期刊: 中国物理B（英文版）
• 关键词: La2-xSrxCuO4 intrinsic electronic phase interstitial oxygen
• 年，卷（期）: 2008,（7）
• 页码范围: 2712-2716
• 页数: 5页
• 语种: 英文

摘要

Strontium and oxygen co-doped La1.937Sr0.063CuO4+δ superconductor with Tc≈40K, which is obtained by oxidizing strontium-doped starting ceramic sample La1.937Sr0.063CuO4 in NaClO solution, is annealed under different conditions to allow interstitial oxygen to redistribute. The evolution of the intrinsic superconducting property with the oxygen redistribution is studied in detail by magnetic measurements in various fields. It is found that there occurs the electronic phase separation from the single superconducting phase with Tc≈40K into two coexisting superconducting states with values of Tc: 15 and 40K or of 15 and 35K in this system, depending on annealing condition. Our results indicate that the 15, 35 and 40K superconducting phases associated with the excess oxygen redistribution are all thermodynamically meta-stable intrinsic states in this Sr/O co-doped cuprate.