The structure and properties of the manganate with nominal composition La1.0Ca2.0Mn2O7

The manganate with nominal composition La1.0Ca2.0Mn2O7 was prepared using a standard solid-state reaction method under ambient pressure. The structure of the compound was investigated using powder X-ray diffraction, Rietveld analysis and TEM experiments. The results show that the compound forms multiphase mixtures comprising the layered perovskite manganate La1.0Ca2.0Mn2O7 with 91.3% weight fraction as majority phase, the perovskite manganate La0.5Ca0.5MnO3 with weight fraction 8.7% as the minority phase. The occurrence of weak magnetization at 250 K and the presence of weak magnetization in the lower temperature region of 5–135 K are linked to the perovskite manganate La0.5Ca0.5MnO3 and the layered perovskite manganate La1.0Ca2.0Mn2O7, respectively. The magnetoresistance (MR) occurred in the lower temperature range arises mainly from the layered perovskite manganate La1.0Ca2.0Mn2O7.