Enhanced low field magnetoresistance in La0.7Sr0.3MnO3/TiO2 composite
Enhanced low field magnetoresistance in La0.7Sr0.3MnO3/TiO2 composite
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DOI：
10.1088/0022-3727/39/16/002
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发表时间：
2006-08
期刊：
影响因子：
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通讯作者：
A. Gaur;G. D. Varma;H. Singh
中科院分区：
文献类型：
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作者：
A. Gaur;G. D. Varma;H. Singh
采用固相反应法制备了（1-x）La0.7Sr0.3MnO3 + xTiO 2（x = 0，0.05，0.10，0.15和0.20）复合材料。研究了复合材料的微观结构、磁性和输运性能。X射线衍射表明，这两种化合物保持其身份，也就是说，没有证据之间的反应La0.7Sr0.3MnO3和TiO 2。观察到磁化强度随着TiO 2含量的增加而降低。将TiO 2相并入La0.7Sr0.3MnO3基质中降低了金属-绝缘体转变温度（Tp）。低场磁电阻（LFMR）的增强，观察到在温度低于130 K的复合材料与较低的TiO 2含量，即，x = 0.05和x = 0.10。认为这种低温（T < 130 K）LFMR的提高是由于晶界处自旋极化隧穿增强所致。
The (1 − x) La0.7Sr0.3MnO3 + xTiO2 (x ∼ 0, 0.05, 0.10, 0.15 and 0.20) composites were prepared via a solid-state reaction process. The microstructural, magnetic and transport properties of the composites were investigated. X-ray diffraction reveals that both the compounds maintain their identities, that is, there is no evidence of reaction between the La0.7Sr0.3MnO3 and TiO2. Magnetization is observed to decrease as the TiO2 content is increased. Incorporation of a TiO2 phase into the La0.7Sr0.3MnO3 matrix lowers the metal–insulator transition temperature (Tp). An enhancement in low field magnetoresistance (LFMR) is observed at temperatures below 130 K for the composites with lower TiO2 content, namely, x = 0.05 and x = 0.10. It is argued that this improved LFMR at low temperature (T < 130 K) arises from the enhanced spin-polarized tunnelling at the grain boundaries.