Simultaneous observation of positive and negative giant magnetoresistances in composite (La0.83Sr0.17MnO3) 1-x(ITO)x

• 来源期刊: 中国物理（英文版）
• 关键词: granular system composite giant magnetoresistance p-n heterostructure
• 年，卷（期）: 2006,（4）
• 页码范围: 850-853
• 页数: 4页
• 语种: 英文

摘要

We have studied the transport property of the composites (La0.83Sr0.17 MnO3)l-x(ITO)x[ITO=(In2O3) 0.95 (SnO2)0.05],which were fabricated by mechanically mixing La0.83Sr0.17MnO3 and ITo grains. A giant positive magnetoresistance (PMR) has been observed above the Curie temperature Tc for samples with x around 0.40,in addition to the negative magnetoresistance related to spin-dependent interfacial tunnelling below Tc.Fbr (La0.83Sr0.17MnO3) 0.6(ITO)0.4,the magnetoresistive ratio for the PMR can reach 39.3% under a magnetic field H=2.24x105A/m.Theoretical analysis suggests that the magnetic-field-induced broadening of the p-n barrier between both kinds of grains and the density of the p-n heterostructures should be responsible for the PMR behaviour.