Electrical properties of In³⁺and Cr³⁺substituted magnesium–manganese ferrites

Abstract

Two series of magnesium–manganese ferrites, viz. Mg0.9Mn0.1InxFe2 − xO4 and Mg0.9Mn0.1CryFe2−yO4 have been prepared by the conventional ceramic process. The effects of In3+ and Cr3+ ions on the dc resistivity, dielectric constant and dielectric loss factor are presented in this paper. The resistivity increases with increasing concentrations of In3+ and Cr3+ ions. The observed variations in resistivity have been explained by Verwey's hopping mechanism. The activation energy, deduced from the temperature variation of resistivity, was found to increase with increasing concentrations of In3+ and Cr3+ ions. The room temperature dielectric constant at 100 kHz decreases with successive addition of trivalent ions in both the series. The observed variation in dielectric constant has been explained on the basis of space charge polarization. The dielectric loss tangent (tanδ) values measured at 100 kHz and 13 MHz are found to be very low for the samples with a higher concentration. The low values of the loss factor even at a high frequency indicate that the prepared materials may have great potential for use in microwave devices.

Structure and electrical properties of Co0.5CdxFe2.5−xO4 ferrites

“…The hopping between A -A sites does not exist, due to that there are only Fe 3+ ions at A sites and any Fe 2+ ions formed during processing preferentially occupy B sites only [19]. The charges can migrate under the influence of the applied field contributing to the electrical response of the system.…”

Magneto-resistive coefficient enhancement observed around Verwey-like transition on spinel ferrites XFe2O4 (X = Mn, Zn)

“…Therefore, when a magnetic field is applied the conduction could be facilitated through a spin driven conduction, giving place to the observed magnetoresistive effect on these ferrites. [12][13][14]17,18 Even though a good understanding on the Verwey-like transition is not clear yet, the fact that the conduction phenomena are affecting directly in the MRC could lead to a better understanding of this electrical transitions and its origin.…”

“…Here, the hopping probability depends on the separation of the ions and on the activation energy, which at the same time is dependent on temperature. [9][10][11][12][13][14] The magnetoresistive response has been found in some ferrite systems, which makes them more interesting for technological applications. 9,15 Therefore, in order to understand magnetoresistive phenomena, it is interesting to study the origin of the electrical resistance behavior during electrical transitions, and its effect on the magnetoresistance coefficient.…”

Effects of Co-substitution on wide temperature ranging characteristic of electromagnetic properties in MnZn ferrites

“…The hopping probability not only depends upon the separation between the ions involved but also the activation energy [18]. The activation energy of each sample in the measured temperature range can be determined by the temperature dependence of DC resistivity [19].…”