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用溶胶_凝胶方法制备了1/mAg2O_La0.833K0.167MnO3(LKMO/Ag)系列样品,其中1/m代表Ag2O和La0.833K0.167MnO3(LKMO)的摩尔比,m=32,16,8,4和2.研究了此系列样品的结构、磁性和输运特性.X射线衍射实验表明,LKMO/Ag是一个非均匀的系统,样品由磁性的钙钛矿相LKMO和金属Ag相组成.由于Ag相的加入,在室温条件下,磁电阻效应明显增强.在300K,0.5T磁场下,m=4样品的磁电阻可以达到32%;5.5T磁场下,其磁电阻可达64%.而单纯的LKMO样品在相同条件下的磁电阻分别为10%和35%.在低温下,加Ag样品的磁电阻效应反而减小,样品含Ag越多,磁电阻效应越小.用非本征磁电阻(包括自旋极化隧穿和自旋相关散射)和本征磁电阻在不同温区对总磁电阻的相对贡献对此系列样品的磁电阻现象作了定性的解释.
A series of 1 / mAg2O_La0.833K0.167MnO3 (LKMO / Ag) samples were prepared by the sol-gel method, where 1 / m represents the molar ratio of Ag2O and La0.833K0.167MnO3 (LKMO), m = 32, 4 and 2. The structure, magnetism and transport properties of this series of samples have been studied.The X-ray diffraction experiments show that LKMO / Ag is a non-uniform system and the sample consists of magnetic perovskite phase LKMO and metallic Ag phase. When the Ag phase is added, the magnetoresistance effect is obviously enhanced at room temperature, and the magnetoresistance of the sample with m = 4 can reach 32% under the magnetic field of 300K and 0.5T, and the magnetic resistance can reach 64% under the 5.5T magnetic field. The magnetoresistance of the pure LKMO sample under the same conditions were 10% and 35%, respectively. At low temperature, the magnetoresistance effect of the Ag sample was reduced, but the more the sample containing Ag, the less the magnetoresistance effect. The relative contribution of magnetoresistance (including spin-polarized tunneling and spin-dependent scattering) and intrinsic magnetoresistance in different temperature regions to the total magnetoresistance provides a qualitative explanation of the magnetoresistance of this series of samples.