Synthesis of Bi₂₅FeO₃₉ by molten salts method and its mössbauer spectrum

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• 作者：Shirley Sara&iacute ; Flores Morales ; Jes&uacute ; s A. Le&oacute ; n Flores ; Jos&eacute ; Luis P&eacute ; rez Mazariego ; ^{mazariego@ciencias.unam.mx" class="auth_mail" title="E-mail the corresponding author} ; Vivianne Marquina F&aacute ; brega ; Ra&uacute ; l W. G&oacute ; mez Gonz&aacute ; lez
• 关键词：M&ouml ; ssbauer spectroscopy ; Molten salts synthesis ; BiFeO3 ; X-ray diffraction ; Sillenite type structure
• 刊名：Physica B: Physics of Condensed Matter
• 出版年：2017
• 出版时间：1 January 2017
• 年：2017
• 卷：504
• 期：Complete
• 页码：109-111
• 全文大小：280 K

文摘

A sample of Bi₂₅FeO₃₉ was synthesized by the molten salts method in 2 h at 750 °C with KCl-KBr as reaction media. The sample was characterized with X-ray powder diffraction and Mössbauer spectroscopy. The Rietveld refinement of the X-ray diffraction confirms that a sillenite type structure with a cell parameter a=10.190(4) Å was achieved, with only small traces of Bi₂O₃. In order to get a Mössbauer spectrum with a good signal to noise ratio, the synthesis was made using 95% enriched α–⁵⁷Fe₂O₃. To our knowledge, this is the first time that a Mössbauer spectrum for the Bi₂₅FeO₃₉ has been recorded. The nonappearance of a magnetic sextet confirms its paramagnetic behavior. The measured Mössbauer parameters (IS=0.20±0.004 mm/s and QS=0.2±0.07 mm/s) correspond to Fe⁺³ in very symmetric surroundings, and rule out some interpretations given to the doublet observed in some Mössbauer spectra of BiFeO₃.