Local iron ion distribution and magnetic properties of the perovskites La1-xSrxFeO3-γ

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:466

Article

da Silva, R. B.¹  Soares, J. M.¹  da Costa, Jose. A. P.¹  de Araujo, J. H.²  Rodrigues, A. R.³  Machado, F. L. A.³ 

[1] Univ Estado Rio Grande do Norte, Dept Fis, BR-59610010 Mossoro, RN, Brazil

[2] Univ Fed Rio Grande do Norte, Dept Fis Teor & Expt, BR-59072970 Natal, RN, Brazil

[3] Univ Fed Pernambuco, Dept Fis, BR-50670901 Recife, PE, Brazil

关键词: Sol gel method;    Orthoferrites;    Hexaferrites;    Magnetic properties;    Mossbauer spectroscopy;   

DOI  :  10.1016/j.jmmm.2018.07.040

来源: Elsevier

【 摘 要 】

The influence of thermal annealing on the structural and magnetic properties of nanocrystalline La1-xSrxFeO3-gamma perovskites with x = 0, 0.3, 0.4 and 0.5 was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), Mossbauer spectroscopy and magnetization measurements. Samples prepared by a sol gel method were calcined for 4 h at 1073 K and annealed for 8 h at 1273 K. XRD data indicate the formation of single phases in all samples, orthorhombic with the space group Pbnm for x = 0.0 and 0.3 and rhombohedral with the space group R (3) over barc for x = 0.4 and 0.5. The Mossbauer spectroscopy reveal that the sintering process increase the amount of Fe(4+)and decrease the paramagnetic sites. Despite of the XRD data indicating the samples to be single phase, the higher coercivity observed in the samples with x = 0.4 may be associated with the emergence of Sr1-xLaxFe12O19 clusters in the samples. Irreversibility in the measurements of magnetization as a function of temperature was interpreted in terms of a high temperature glass cluster behavior.

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