کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1804286 | 1024646 | 2007 | 7 صفحه PDF | دانلود رایگان |

A series of self-doped La0.9MnO3+δ compounds have been fabricated by the solid-state reaction method with different post-annealing and oxygenation processes. The temperature dependence of resistivity measured at several magnetic fields indicated that all of these samples have an insulator–metal transition with a large negative colossal magnetoresistance (CMR) ratio. The resistivity, maximum CMR ratio and peak position are dominated by the oxygen content. As the oxygen content increases, the resistivity decreases, the peak position shifts to higher temperature and the maximum CMR ratio increases, respectively; meanwhile the peak number in the R–T curve is changed from 1 to 2, then from 2 to 1. The temperature dependencies of magnetization and specific heat show the evidence of magnetic phase transition in these samples. We think that two peaks contributed by the different oxygen-induced ferromagnetic phases resulted in the phase separation of the sample.
Journal: Journal of Magnetism and Magnetic Materials - Volume 311, Issue 2, April 2007, Pages 623–629