Synthesis and characterization of La0.8Sr1.2Co0.5M0.5O4−δ (M=Fe, Mn)

✍ Scribed by H. El Shinawi; J.F. Marco; F.J. Berry; C. Greaves

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 601 KB
• Volume: 182
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1016/j.jssc.2009.06.010

✦ Synopsis

The M 4+ -containing K 2 NiF 4 -type phases La 0.8 Sr 1.2 Co 0.5 Fe 0.5 O 4 and La 0.8 Sr 1.2 Co 0.5 Mn 0.5 O 4 have been synthesized by a sol-gel procedure and characterized by X-ray powder diffraction, thermal analysis, neutron powder diffraction and M össbauer spectroscopy. Oxide ion vacancies are created in these materials via reduction of M 4+ to M 3+ and of Co 3+ to Co 2+ . The vacancies are confined to the equatorial planes of the K 2 NiF 4 -type structure. A partial reduction of Mn 3+ to Mn 2+ also occurs to achieve the oxygen stoichiometry in La 0.8 Sr 1.2 Co 0.5 Mn 0.5 O 3.6 . La 0.8 Sr 1.2 Co 0.5 Fe 0.5 O 3.65 contains Co 2+ and Fe 3+ ions which interact antiferromagnetically and result in noncollinear magnetic order consistent with the tetragonal symmetry. Competing ferromagnetic and antiferromagnetic interactions in La 0.