Effects of thermal treatment on structure and magnetic properties of nonstoichiometric perovskite-type oxides La0.67Sr0.15□0.18MnO3-δ

✍ Scribed by Ge, J. J. ;Yang, M. ;Xue, X. B. ;Du, J. ;Wu, X. S. ;Tan, W. S.

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 346 KB
• Volume: 208
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.201084189

✦ Synopsis

Abstract

The structural and magnetic properties of La~0.67~Sr~0.15~□~0.18~MnO~3‐δ~ manganites obtained with various thermal treatment conditions have been studied. X‐ray diffraction studies show that all the samples crystallize with the rhombohedral symmetry and the space group is R‐3__c__. No change in structural symmetry is found for all samples with thermal treatment. However, the bond angles of MnOMn and O1MnO2 deviate from 180 and 90 °, respectively, indicating the presence of Jahn–Teller type distortion in the MnO~6~ octahedron. And the oxygen content shows determinant affect on compound magnetic properties. With increasing oxygen content induced by thermal treatments, the Curie temperatures T~C~ increases systematically from ∼280 to ∼303 K, showing the dependence of sample magnetic properties on sintering processes. A maximum value of |ΔS~M~(T, H)| is measured to be more than 5 J/kg · K near the curie temperature, indicating the potential of utilizing the strong magnetocaloric effect of these materials in magnetic refrigeration.