Dielectric and Conductor

**45**

**Chapter 3**

**Abstract**

Mg0.5Zn0.5Fe2O4.

dielectric properties

**1. Introduction**

Effect of Transition Metal

(Tm = Zn and Cu) System

size (~ 44.73 nm) has a high dielectric constant (~ 4.41 × 104

**Keywords:** solid-state synthesis, ferrite, crystallite size, X-ray diffraction,

Ferrites are insulating magnetic oxides with high electrical resistance, low dielectric losses, high permeability, and high saturation magnetization. These magnetic materials are special and can be used in several device applications. Transition metal ion-doped spinel ferrites are fascinating due to high dielectric constant and low dielectric losses [1, 2]. Soft ferrite materials such as Mg-Zn ferrites have vast technological importance due to their relatively high Curie temperature, low cost, and eco-friendly stable nature. The transport properties of soft ferrites are mainly controlled by divalent impurities. Further, soft ferrites are used in advanced technologies such as magnetic resonance imaging (MRI), magnetic drug delivery, microwave absorbers, catalysis, detoxification of biological fluids, transformer cores, magnetically controlled transport of anti-cancer drugs, sensors [2].

Spinel ferrites with formula AB2O4 (A = Mg, Zn, Cu) have a cubic structure with an *Fd*3*m* space group. However, MgFe2O4 is having an inverse spinel structure with zero magnetic moments. This inversion is usually affected by the temperature given during calcination, while ZnFe2O4 often has a normal spinel structure without

*Pallavi Saxena and Anand Yadav*

on Structural and Dielectric

Properties of Mg0.5Tm0.5Fe2O4

This study explored the structural and dielectric features of Mg0.5Tm0.5Fe2O4 (Tm = Zn and Cu) that were synthesized by the Solid-state reaction (SSR) method. The X-ray powder diffraction (XRD) analysis reveals that the prepared samples are single-phase cubic structure without any impurity. Rietveld-refined X-ray diffraction results reveal the formation of cubic structure and all the peaks of Mg0.5Zn0.5Fe2O4 and Mg0.5Cu0.5Fe2O4 are perfectly indexed in the cubic (*Fd*-3 *m*) structure. Dielectric constant and dielectric loss variation with frequency were also explored. Both decrease when the relevant alternating field is increasing and become constant at high frequencies which reflects the important role of interfacial polarization. Furthermore, the Mg0.5Cu0.5Fe2O4 having the smallest crystallite

) value as compare to
