Dielectric relaxation behavior of Aub>xub>Coub>1鈭?span style='font-style: italic'>xub>Feub>2ub>Oub>4ub> (A = Zn, Mg) mixed ferrites

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• 作者：Kavita Verma ; Ashwini Kumar ; Dinesh Varshney ; ^{vdinesh33@rediffmail.com} ; ^{vdinesh33@gmail.com}
• 关键词：Chemical synthesis ; X-ray diffraction ; Scanning electron microscopy ; Dielectric response
• 刊名：Journal of Alloys and Compounds
• 出版年：2012
• 期刊代码：45_09258388
• 类别：ms
• 出版时间：15 June, 2012
• 卷：526
• 期：Complete
• 页码：91-97
• 文件大小：1073 K

摘要

Samples of Aub>xub>Coub>1鈭?em>xub>Feub>2ub>Oub>4ub> (A = Zn, Mg; x = 0.0, 0.5) ferrite were synthesized by chemical co-precipitation method. Room temperature Rietveld - refined X-ray diffraction pattern elucidate the formation of single-phase cubic structure with Fd3m space group for all prepared samples. Slight variation in the lattice parameter of Mg doped CoFeub>2ub>Oub>4ub> has been observed when compared with CoFeub>2ub>Oub>4ub> and Znub>0.5ub>Coub>0.5ub>Feub>2ub>Oub>4ub>. The variation of permittivity and ac conductivity as a function of frequency reveals that dispersion in all these ferrites is attributed to Maxwell-Wagner type of interfacial polarization. The minimum value of loss tangent (鈭?.04) at 5 kHz makes Aub>xub>Coub>1鈭?em>xub>Feub>2ub>Oub>4ub> most suitable material for microwave application. Temperature dependent dielectric constant and loss tangent of all the three samples shows an increasing trend with increase in temperature. The activation energy (Eub>aub>) for CoFeub>2ub>Oub>4ub>, Coub>0.5ub>Mgub>0.5ub>Feub>2ub>Oub>4ub> and Coub>0.5ub>Znub>0.5ub>Feub>2ub>Oub>4ub> were found to be 0.81 eV, 0.76 eV and 0.63 eV respectively. The electrical modulus study clearly reveals the presence of non-Debye type of dielectric relaxation in the present material.