Temperature and frequency dependence of electromagnetic properties of sintering Li–Zn ferrites with nano SiO2 additive

• Nano-SiO2 played a very significant role in improving magneto-dielectric properties.
• Density and grain growth rate were sensitive to sintering temperature and nano-SiO2.
• The frequency distribution of εandtanδ were explained according to Koops' theory.
• 2 wt% is the optimum amount to attain the desired electromagnetic properties.

The goal of this paper was to investigate the effect of the addition of nano-silica (<20 nm) and the sintering temperature on the magneto-dielectric properties of Li0.30Zn0.4Fe2.30O4 ferrites produced by the conventional method in various temperatures (298–673 K) and frequencies (1 KHz–4 MHz). The density and microstructural results revealed that density and grain growth rate were sensitive to the sintering temperature and nano-SiO2 content. At low amounts of SiO2 (2 wt%), an increase in nano-SiO2 content increased the density and grain growth rate. SiO2 contents Higher than 2 wt% caused a decrease in the grain size of samples. Moreover, the sample with the highest grain size showed the highest permeability and the lowest magnetic loss. On the other hand, ε′ showed a dispersive behavior with frequency for all samples. The frequency dependence of tan δ showed a resonance peak. It was observed that ε′ and tan δ were increased with the increase in the temperature. Furthermore, the variation of magneto-dielectric properties as a function of frequency were explained according to Koops' theory and electron hopping between the Fe+2 and Fe+3 ions.

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