Structural, magnetic and spectral properties of Gd and Dy co-doped dielectrically modified Co-Ni (Ni<sub>0.4sub>Co<sub>0.6sub>Fe<sub>2sub>O<sub>4sub>) ferrites
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- 作者：Allah Ditta<sup>asup> ; Muhammad Azhar Khan<sup>asup><sup> ; sup><sup>azhar.khan@iub.edu.pksup> ; Muhammad Junaid<sup>asup><sup> ; sup><sup>junaid.malik95@yahoo.comsup> ; R.M. Arif Khalil<sup>bsup> ; Muhammad Farooq Warsi<sup>csup>
- 关键词：Spinel nanoferrites ; TGA ; XRD ; FTIR ; Magnetic properties ; Dielectric properties
- 刊名：Physica B: Condensed Matter
- 出版年：2017
- 出版时间：15 February 2017
- 年：2017
- 卷：507
- 期：Complete
- 页码：27-34
- 全文大小：1105 K
- 卷排序：507
文摘
Gadolinium (Gd) and Dysprosium (Dy) co-doped Ni-Co (Ni0.4Co0.6Fe2O4) ferrites were prepared by micro-emulsion route. X-ray diffraction (XRD) analysis indicated the development of cubic spinel structure. The lattice parameter and X-ray density were found to increase from 8.24 to 8.31 Å and 5.57 to 5.91 (gm/cm3) respectively as the Gd-Dy contents increased in nickel-cobalt ferrites. The crystallite size calculated from the Scherrer's formula exhibited the formation of nanocrystalline ferrites (13–26 nm). Two foremost absorption bands observed in FTIR spectra within 400 cm−1 (υ2) to 600 cm−1 (υ1) which correspond to stretching vibrations of tetrahedral and octahedral complexes respectively. The dielectric constant (ε) and dielectric loss (tanδ) were decreased by the optimization of frequency and abrupt decrease in the low frequency region and higher values in the high frequency region were observed. The dielectric dispersion was due to rapid decrease of dielectric constant in the low frequency region. This variation of dielectric dispersion was explicated in the light of space charge polarization model of Maxwell-Wagner. The dielectric loss occurs in these ferrites due to electron hopping and defects in the dipoles. The electron hopping was possible at low frequency range but at higher frequency the dielectric loss was decreased with the decrease of electron hopping. Magnetic properties were observed by measuring M-H loops. Due to low dielectric loss and dielectric constant these materials were appropriate in the fabrication of switching and memory storage devices.