物理化学学报 >> 1997, Vol. 13 >> Issue (12): 1079-1083.doi: 10.3866/PKU.WHXB19971205

研究论文 上一篇    下一篇

La0.67Sr0.33FexMn1-xO3制备和奇特磁电阻效应

李亚栋,章建辉,朱长飞,刘卫,熊曹水,周移,钱逸泰   

  1. 中国科学技术大学结构成分开放实验室,合肥 230026|中国科学技术大学化学系,合肥 230026|中国科学技术大学内耗与固缺陷体开放实验室,合肥 230026
  • 收稿日期:1997-02-03 修回日期:1997-05-05 发布日期:1997-12-15
  • 通讯作者: 李亚栋

Preparation and Pecuiar Magnetoresistance of La0.67Sr0.33FexMn1-xO3

Li Ya-Dong,Zhang Jian-Hui,Zhu Chang-Fei,Liu Wei,Xiong Cao-Shui,Zhou Yi,Qian Yi-Tai   

  1. Structure Reaserch Laboratory,Academia Sinica,Hefei 230026|Chemistry Department,University of Science and Technology of China,Hefei 230026|Laboratory of Interner Friction and Defects in Solid Academia Sinica,Hefei 230026
  • Received:1997-02-03 Revised:1997-05-05 Published:1997-12-15
  • Contact: Li Ya-Dong

摘要:

系列陶瓷氧化物La0.67Sr0.33FexMn1-xO3(0.055≦x≦0.33)通过共沉淀法工艺合成获得. 经X射线衍射分析表明,所得氧化物均为单相,属三方结构. 在零场和外加磁场下的四极法电阻测试结果表明:所有样品都具有较大的磁电阻效应,当x≦0.13时,样品的电阻率-温度曲线中均出现电阻率峰(电阻率出现从半导体性向金属性的转变),该电阻率峰处的温度(Tp)随x的增大而向低温区移动,磁电阻效应是负值; x=0.23时,样品已呈半导体性,磁电阻效应仍是负值; 然而x=0.33时,样品虽也表现为半导体性,但其中的磁电阻效应出现奇特的正负交替转换.

关键词: 共沉淀工艺, 三方结构, 巨磁电阻效应

Abstract:

 The Ln0.67Sr0.33Fe.Mn1-xO3(LSFMO)(0.05< x <0.33) systems have been synthesized by co-precipitation. The X-ray diffraction patterns indicates that these compounds are of single phase with rhombohedral structure. The resistivity of samples was measured in zero field and applied field (H=4000Oe) by a standard four-probe method. Large magnetoresistance (MR) was found in all samples. There is a resistivity transition peak in LSFMO (x ≦0.13) in which MR negative, the temperature (TP) at which the resistivity peak occurs decreases with the increasing of x. LSFMO (x=0.23) to which the large negative MR is still found is a semiconductor, It is unexpected that a peculiar alternative positive negative MR was found in LSFMO(x=0.33) which also is a semicondutor.

Key words: Co-precipitation, Route, Rhombohedral structure, Magnetoresistance