La_(0.67)Sr_(0.33)Fe_xMn_(1-x)O_3制备和奇特磁电阻效应 |
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引用本文: | 李亚栋,章建辉,朱长飞,刘卫,熊曹水,周移,钱逸泰. La_(0.67)Sr_(0.33)Fe_xMn_(1-x)O_3制备和奇特磁电阻效应[J]. 物理化学学报, 1997, 0(12) |
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作者姓名: | 李亚栋 章建辉 朱长飞 刘卫 熊曹水 周移 钱逸泰 |
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作者单位: | 中国科学技术大学结构成分开放实验室!中国科学技术大学化学系,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,中国科学技术大学内耗与固缺陷体开放实验室!合肥,230026,中国科学技术大学结构成分开放实验室!合肥,2300 |
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摘 要: | 系列陶瓷氧化物La0.67Sr0.33FexMn1-xO3(0.055x0.33)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.
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关 键 词: | 共沉淀工艺 三方结构 巨磁电阻效应 |
Preparation and Peculiar Magnetoresistance of Ln_(0.67)Sr_(0.33)Fe_xMn_(1-x)O_3 |
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Abstract: | The Ln0.67Sr0.33Fe.Mn1-xO3(LSFMO)(0.05< x <0.33) systerns have been synthesized by co-precipitation. The X-ray diffraction patterns indicates that these conrpounds 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=o.23) to which the large negative MR is stin found is a sendconductor, It is unexpected that a peculfor alternative positive negative MR was found in LSFMO(x=0.33) which also is a semicondutor. |
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Keywords: | Co-precipitation Route Rhombohedral structure Magnetoresistance |
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