Substantial Enhancements of Low-Field Magnetoresistance at Temperatures near77 K with Doping 4% Cu at Mn Sites of La2/3Ca1/3MnO3 Synthesized at 1000℃

• 来源期刊: 中国物理快报（英文版）
• 学科: 物理学
• 年，卷（期）: 2002,（12）
• 页码范围: 1866-1869
• 页数: 4页
• 分类号: O4
• 语种: 英文

摘要

We report on investigations of magnetoresistance (MR) in polycrystalline La2/3Ca1/3Mn1-xCuxO3 (x = 0 and 4%) samples prepared by the sol-gel method followed a sintering treatment at 1000℃. For the x = 4% sample, the most remarkable MR effect appears at temperatures near 77K and for magnetic fields lower than 1 T. For fields ～ 0.3 T and at temperatures ～ 77 K, the x = 4% sample exhibits a giant MR effect with Mro (≡△p/p (H = 0)) between ～ 50 and ～ 70%, comparable to the so-called colossal MR response observed in the x = 0 sample for the 3 T field.