Oxygen content and magnetic properties of composites La sub(0.75)Sr sub(0.25)MnO sub(3 plus or minus delta ) calcined at different temperatures

• Published in: Rare metals 2014-08, Vol.33 (4), p.452-458
• Main Authors: Ji, Deng-Hui, Hou, Xue, Tang, Gui-De, Li, Zhuang-Zhi, Hou, Deng-Lu, Zhu, Ming-Gang
• Format: Article
• Language: English
• Subjects: Calcination; Crystallites; Curie temperature; Magnetic properties; Manganites; Oxygen content; Roasting; Saturation (magnetic)
• ISSN: 1001-0521; 1867-7185
• DOI: 10.1007/s12598-013-0093-2

(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).The effects of the calcination temperature on the oxygen content and magnetic properties of the nanocrystalline perovskite manganite La sub(0.75)Sr sub(0.25)MnO sub(3 plus or minus delta ) prepared 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 ... 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 temperature are successfully explained.