Oxygen content and magnetic properties of composites Lao.75Sro.25Mn03＋δcalcined at different temperatures

• Published in: 稀有金属：英文版 2014 (4), p.452-458
• Main Author: Deng-Hui Ji Xue Hou Gui-De Tang Zhuang-Zhi Li Deng-Lu Hou Ming-Gang Zhu
• Format: Article
• Language: English
• Subjects: 化学计量; 复合材料; 居里温度; 氧含量; 焙烧温度; 煅烧; 磁性能; 饱和磁化强度
• ISSN: 1001-0521; 1867-7185

The effects of the calcination temperature on the oxygen content and magnetic properties of the nano- crystalline perovskite manganite Lao.75Sro.25MnO3±δ pre- pared by the sol-gel method were investigated. The highest temperatures at which the samples were calcined were 973, 1073, 1273, and 1473 K. The X-ray diffraction （XRD） analyses indicate that all the samples have only a single phase with the R3c perovskite structure. As the calcination temperature and calcination time increase, the oxygen content in the samples increases from being deficient to being in excess of that in the stoichiometric formula. The crystallite size also increases from 23 to 283 nm. Magnetic measurements indicate that the sample calcined at 1073 K has the highest Curie temperature. This is owing to the fact that the crystallite cores of this sample have stoichiometric oxygen content. The dependence of the Curie temperature and the saturation magnetization on the calcination tem- perature are successfully explained.