铜含量对La_(2/3)Sr_(1/3)MnO_3的电输运及磁电阻的影响  

Effect of Cu Content on Electrical Transport and Magnetoresistance of (1-x)La_(2/3)Sr_(1/3)MnO_3/xCu Composite

作　　者：刘莉[1] 袁松柳[1] 肖循[1] 王永强[1] 任光明[1] 

机构地区：[1]华中科技大学物理系,湖北武汉430074

出　　处：《中国稀土学报》2006年第6期695-700,共6页Journal of the Chinese Society of Rare Earths

基　　金：国家自然科学基金资助项目(1017402210374032)

摘　　要：先用溶胶-凝胶法制备出La2／3Sr1/3MnO3的颗粒系统，然后用化学的方法将Cu材料引入到La2／3Sr1/3MnO3的颗粒表面，形成（1-x）La2／3Sr1/3MnO3／xCu（x≤0．05）的复合样品。实验表明：Cu含量较低（x〈0．02）时，复合样品电阻率较大，仅在低温区表现出大的磁电阻效应，Cu含量较高（x〉0．025）时，复合样品的电阻率较小（～10^-2Ω·cm），在室温附近（270～300K）、3T的磁场下，表现出较大的不随温度变化的磁电阻效应～10％。The La2/3Sr1/3MnO3 polycrystalline samples were prepared. The Cu-bearing materials were introduced into the surface of La2/3Sr1/3MnO3 grains chemical route, and in this way （1 - x ）La2/3Sr1/3MnO3/xCu （x ≤0. 05） composite samples were formed. The resistivity dependences of temperature in zero field and applied field were measured. In the samples with low Cu content （x 〈 0.02）, the resistivity is high and magnetoresistance （MR） occurs only at low temperatures; in the samples with high Cu content （x 〉 0.025）, the resistivity is as low as ～ 10^-2, and the MR under a magnetic field of 3 T is a constant value （ ～ 10%） near room temperature （270- 300 K）.

关 键 词：磁电阻 溶胶-凝胶 自旋极化隧穿 颗粒边界 稀土 

分 类 号：TM271[一般工业技术—材料科学与工程]