Dielectric Behaviour of Lithium-Cadmium Ferrites

Abstract

The dielectric constant (\documentclass{article}\pagestyle{empty}\begin{document}$ \varepsilon ' $\end{document}) and dielectric loss tangent (tan δ) of mixed Li‐Cd ferrites of various compositions are measured at room temperature in the frequency range 1 to 100 kHz using a capacitance bridge. Plots of dielectric constant (\documentclass{article}\pagestyle{empty}\begin{document}$ \varepsilon ' $\end{document}) versus frequency show a normal dielectric behaviour of spinel ferrites. The frequency dependence of dielectric loss tangent (tan δ) is found to be abnormal, giving a peak at a certain frequency for all the samples of Li‐Cd ferrites. However, Li0.3Cd0.4Fe2.3O4 does not show a peak in the frequency range 1 to 100 kHz. A qualitative explanation is given for the composition and frequency dependence of the dielectric constant and dielectric loss tangent. The dielectric constant for these mixed ferrites is approximately inversely proportional to the square root of the resistivity.

Study of Dielectric Properties of Nano-crystalline Mn-Zn Ferrite

“…It can be seen from the table that the ' is roughly inversely proportional to the square root of resistivity and the product '  remains nearly constant as shown in the Table 1. A similar relationship between ' and   was found by Ravinder [16] for different ferrites. The dielectric losses in ferrites are generally reflected in the resistivity measurements, materials with low resistivity exhibiting high dielectric losses and vice versa [17].…”

Transport Properties of Polycrystalline Mixed Copper-Zinc Ferrites

“…The changes in the dielectric constant and electrical conductivity is due to the exchanges of electrons between Fe 2+ and Fe 3+ ions which is also responsible for this inverse variation. Such type of similar relationship was found by Koop for Ni-Zn ferrite, Ravinder 31 for Li-Zn ferrite and Shaikh 13 for Li-Zn ferrite. Thus the high electrical resistivity along with low dielectric constant is expected to fulfill the requirement of microwave applications.…”

Influence of zinc substitution on magnetic and electrical properties of MgCuZn ferrite nanocrystalline powders prepared by sol–gel, auto-combustion method

“…The decrease of dielectric constant with increase of frequency as observed in the case of mixed MgZn ferrites is a normal dielectric behavior of spinel ferrites [24]. The normal dielectric behavior was also observed by several investigators in the case of NiZn [25], LiCd [26], LiTiZn [27] and MnZn [28] ferrites. It can be seen from the figure that the dispersion in ε is analogous to Maxwell-Wagner interfacial polarization [29,30], in agreement with Koops phenomenological theory [31].…”