Charge Transfer and Normal State Anomaly in Bi-Based High T_c Superconductors Studied by Positron Annihilation

• 来源期刊: 原子核物理：英文版
• 学科: 物理学
• 关键词: Bi-based SUPERCONDUCTORS Charge transfer Normal state ANOMALY Positron annihilation
• 年，卷（期）: 1994,（3）
• 页码范围: 278-282
• 页数: 5页
• 分类号: O4

摘要

【正】 The positron annihilation lifetime and Doppler broadened line-shapeparameter have been measured between 77 and 300 K for Bi_1.8Pb_0.1Sb_0.1Sr₂Ca₂Cu₃O_x,Bi_1.8Sb_0.2Sr₂Ca₂Cu₃O_x and Bi_1.7Pb_0.2Sb_0.1Sr₂Ca₂Cu₂O_x. The charge transfer from Cu-Olayers to Bi-O layers has been observed across T_cs for all samples.Three samples allshow two normal state anomalies around 160 K and 240 K,respectively.The anomalyaround 160 K is attributed to the structural instability and that around 240 Kpresumably to the displacement phase transition.