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Effects of thermal treatment on structure and magnetic properties of nonstoichiometric perovskite‐type oxides La 0.67 Sr 0.15 □ 0.18 MnO 3‐ δ
Author(s) -
Ge J. J.,
Yang M.,
Xue X. B.,
Du J.,
Wu X. S.,
Tan W. S.
Publication year - 2011
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201084189
Subject(s) - magnetic refrigeration , curie temperature , octahedron , materials science , perovskite (structure) , crystal structure , manganite , condensed matter physics , jahn–teller effect , sintering , analytical chemistry (journal) , crystallography , magnetization , ferromagnetism , chemistry , metallurgy , ion , magnetic field , physics , organic chemistry , quantum mechanics , chromatography
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 MnOMn and O1MnO2 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.