(1-x)La_(0.6)Dy_(0.1)Sr_(0.3)MnO_3/(x/2)(Sb_2O_3)复合体系磁电阻及其温度稳定性

Magnetoresistance and its temperature stability of (1-x)La_(0.6)Dy_(0.1)Sr_(0.3)MnO_3/(x/2)(Sb_2O_3) composite system

用固相反应法制备了纯La0.6Dy0.1Sr0.3MnO3和(1-x)La0.6Dy0.1Sr0.3MnO3/(x/2)(Sb2O3)样品,研究了样品的电输运性质及高温磁电阻温度稳定性。结果表明,零场下,纯La0.6Dy0.1Sr0.3MnO3的ρ-T曲线出现双峰现象,高温峰是本征峰,较低温出现"肩峰"是非本征峰,复合体系在较低温的"肩峰"消失,用晶界效应予以解释;样品的电输运机制是,母体La0.6Dy0.1Sr0.3MnO3用ρ=ρ0+AT2拟合比较合理,复合样品用ρ=ρ0+AT2.5拟合比较合理;复合样品的MR-T曲线在高温出现一个平台,本征与非本征磁电阻的竞争结果是在高温区出现磁电阻平台,实现了高温区磁电阻的温度稳定性。

PureLa0.6Dy0.1Sr0.3MnO3 and（1-x）La0.6Dy0.1Sr0.3MnO3/（x/2） （Sb2O3）samples were prepared bysolid-state reaction method. The electric transport property and high temperature stability of magnetoresistance werestudied. The results indicated that, in zero field, the p-T curve of pureLa0.6Dy0.1Sr0.3MnO3/（x/2） （Sb2O3）exhibits the double-peakphenomenon, the peak at high temperature is an intrinsic peak, and the ＂shoulder peak＂ at lower temperature is an extrinsic peak, but the ＂shoulder peak＂ disappears in the composite sample, which can be explained by the grain boundary effect; theelectric transport mechanism of the original material La0.6Dy0.1Sr0.3MnO3 can be fitted by formula p=p0＋AT^2, and that of the composite sample can be fitted by formula p=p0＋AT^2.5;the MR-T curve of the composite sample exhibits a platform athigher temperature, which results from the competition between intrinsic and extrinsic magnetoresistance.