Mossbauer characterisations and magnetic properties of iron cobaltites CoxFe3-xO4 (1 ≤ x ≤ 2.46) before and after spinodal decomposition

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:334

Article

Le Trong, H.^1,2  Presmanes, L.¹  De Grave, E.³  Barnabe, A.¹  Bonningue, C.¹  Tailhades, Ph.¹ 

[1] Univ Toulouse, UPS, INP, Inst Camot CIRIMAT UMR CNRS 5085, F-31062 Toulouse 9, France

[2] Vietnam Natl Univ HoChiMinh City, Univ Sci, Fac Chem, Ho Chi Minh City 769999, Vietnam

[3] Univ Ghent, Dept Phys & Astron, NUMAT, B-9000 Ghent, Belgium

关键词: Spinel oxide;    Cobaltite;    Mossbauer;    Spinodal decomposition;   

DOI  :  10.1016/j.jmmm.2013.01.007

来源: Elsevier

【 摘 要 】

Iron cobaltite powders CoxFe3-xO4 (1 <= x <= 2.46) were synthesized with compositions in between the cobalt ferrite CoFe2O4 and Co2.46Fe0.54O4. The cationic distribution of pure spinel phases was determined by Mossbauer spectroscopy: as Co content increases in the spinel oxide, Co3+ cations replace Fe3+ cations in the octahedral sites and Co2+ cations migrate from octahedral to tetrahedral sites. Saturation magnetizations M-s measured at 5 K by a SQUID magnetometer were consistent with the values calculated from the cationic distribution. Ms decreases as diamagnetic Co3+ cations replace strongly magnetic Fe3+ cations. Two spinel phases were formed by spinodal decomposition of Co1.73Fe1.27O4 phase submitted to a subsequent thermal treatment, one with a high amount of iron Co1.16Fe1.84O4 and one other containing mostly cobalt Co2.69Fe0.31O4. Increase of the experimental M-s value obtained after the spinodal decomposition is in accordance with the calculated value deduced from the cationic distribution of the two phases. (C) 2013 Elsevier B.V. All rights reserved.

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