Effect of Nickel Ions Substitution on the Structural and Electrical Properties of a Nanosized Lithium-iron Ferrite Obtained by the Sol-gel Auto-combustion Method

Authors L.S. Kaykan1 , J.S. Mazurenko2 , I.P. Yaremiy1 , Kh.V. Bandura2, N.V. Ostapovych2

1Vasyl Stefanyk Precarpathian National University, 57, Shevchenko St., 76018 Ivano-Frankivsk, Ukraine

2Ivano-Frankivsk National Medical University, 2, Halytska St., 76000 Ivano-Frankivsk, Ukraine

Issue Volume 11, Year 2019, Number 5
Dates Received 21 June 2019; revised manuscript received 21 October 2019; published online 25 October 2019
Citation L.S. Kaykan, J.S. Mazurenko, I.P. Yaremiy, et al., J. Nano- Electron. Phys. 11 No 5, 05041 (2019)
DOI https://doi.org/10.21272/jnep.11(5).05041
PACS Number(s) 71.20.Nr, 72.15.Eb, 72.20.Pa, 77.22.Gm, 73.22. – f, 76.80. + y
Keywords Ferrites (5) , Sol-gel auto-combustion, X-ray diffraction (19) , Conductive and dielectric properties.

Li0.5 – x/2NixFe2.5 – x/2O4 (х ( 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) ferrite spinels have been synthesized by sol-gel auto-combustion technique. Structural properties of the obtained powders have been investigated by X-ray diffraction (XRD) method and scanning electron microscopy (SEM). All the synthesized powders have good crystallinity and it is possible to distinguish two spinels of the same composition: the first one of P4332 spatial group (iron and lithium ions are arranged along (110(crystallographic direction) and the second one of Fd3m spatial group (disordered spinel). The presence of both spinels is observed at low content of the doping material (х ( 0.2 and 0.4). In the case of increase in Ni2+, the disordered component is absent and there is only the ordered phase. The particle size values of the synthesized material are calculated using Debye-Scherrer and Williamson-Hall methods. They are of about 22-35 nm. The presence of internal lattice stresses has been detected. According to proposed cation distribution, nickel ions are localized in tetrahedral sublattice and lithium ions are localized in octahedral one. Iron ions are redistributed in both sublattices in the ratio of about 1:2. The Mossbauer spectra represent a superposition of two magneto-ordered components corresponding to the octahedral and tetrahedral surroundings of iron in the spinel lattice and the paramagnetic doublet that indicates the presence of iron in the bivalent state. It is shown that the conductive and dielectric properties of the synthesized powders are characterized by frequency dependence that is characteristic for ferrite materials. The behavior of this dependence is explained on the basis of the hopping mechanism of conductivity and intergranular polarization.

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