Abstract
We report the synthesis of Y-substituted Mg–Zn [Mg0.5Zn0.5Y x Fe2−x O4 (0 ≤ x ≤ 0.05)] ferrites using conventional standard ceramic technique. The samples were characterized by x-ray diffraction (XRD) analysis, field emission scanning electron microscopy (FESEM), FTIR spectroscopy, UV–Vis spectroscopy and quantum design physical properties measurement system (PPMS). XRD patterns confirm the single phase cubic spinel structure up to x = 0.03 and appearance of a secondary phase of YFeO3 for higher Y contents. FESEM images depict the distribution of grains and EDS spectra confirmed the absence of any unwanted element. Completion of solid state reaction and formation of spinel structure has been revealed from FTIR spectra. The FTIR data along with lattice constant, bulk density and porosity were further used to calculate the stiffness constant (C ij), elastic constant and Debye temperatures. Mechanical stability of all studied compositions is confirmed from C ij using Born stability conditions. Brittleness and isotropic nature are also confirmed using Poisson’s ratio and anisotropy constants, respectively. The enhancement of dc electrical resistivity (105Ω cm to 106Ω cm) with Y content is observed. The energy band gap (increased with Y contents) is found in good agreement with dc electrical resistivity. Ferrimagnetic to paramagnetic phase change has been observed from the field dependent high temperature magnetization curves. The magnetic moments and saturation magnetization were found to be decreased with increasing temperature. The Curie temperature (Tc) has been measured from temperature dependent magnetic moment (M-T) and initial permeability (μ′i-T) measurements and found to be in good agreement with each other. Decrease in Tc with Y content is due to redistribution of cations and weakening of the exchange coupling constant. The magnetic phase transition has been analyzed by Arrott plot and found to have second order phase transition. The dc resistivity endorses the prepared ferrites are suitable for high frequency and high temperature magnetic device applications as well.
Highlights
Since last century, the spinel type ferrites have come out as one of the leading materials in the field of materials science due to their vast applications
The calculated stiffness constant revealed the mechanical stability of the compositions
The bulk modulus is increased for substituted compositions up to x = 0.2 and decreased thereafter
Summary
The spinel type ferrites have come out as one of the leading materials in the field of materials science due to their vast applications. The physics involved in spinel structure is still interesting as their properties can be tuned, their applications as well. Mg-Zn ferrites with higher resistivity (106–107 Ω-cm) make its suitability in high frequency applications [13]. The Zn2+ ions have a preference to occupy A-sites in the spinel lattice [16, 17]. The physical properties of the Mg-Zn ferrites are determined by the cations distribution over the A- and B-sites. The physical properties can be altered by introducing the different metallic ions results the cations distribution modification on the A- and B-sites. The factors that determine cation distributions are ionic radius, charge, site preference and level of substituent ion, methods, conditions and sintering temperature for the preparation of ferrites [19,20,21,22]
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