A Theoretical Approach: Effects of &amp;lt;i&amp;gt;Mn&amp;lt;/i&amp;gt; Substitution in &amp;lt;i&amp;gt;Cobalt&amp;lt;/i&amp;gt; Ferrite

Md Ziaul Ahsan,Md Aminul Islam

doi:10.11648/j.ajasr.20190503.12

Abstract

This paper reports on the effect of Mn substitution in cobalt ferrite to explore the probable correlation among the structural, magnetic, and magneto-mechanical properties by a theoretical approach. Three compositions of Mn doped Cobalt ferrites at different Mn concentration (x) = 0.125, 0.25, 0.375, 0.5 have been undertaken for their analytical study to understand the correlation among the aforesaid properties. In this approach, an empirical equation has been formulated based on idealistic cation distribution in tetrahedral and octahedral sites of cobalt ferrite at room temperature. The hopping lengths and bond lengths have also been estimated using the corresponding Stanley’s equations in idealistic condition. The estimated lattice constant is found to decrease and effective magnetic moment μferri to increase with the Mn content, substituted for Co in the octahedral site due to increased A-B interactions. This increasing effect of Mn content in cobalt ferrite may be significant to the tunability of the Curie temperature, TC and may have an influence on superparamagnetism (SPM). On the other hand, the compositions where Mn substituted for Fe may increase the porosity due to their increased bond lengths with Mn content and thus may optimize them for applications in the environmental (gas) sensors. However, the analysis of the predicted effects of Mn and correlation thereon is completely based on the theoretical approach and thereby need experimental verification to confirm and supplement them.

Highlights

Cobalt ferrites are reported as the best-known examples of the hard ferrite materials because of their excellent chemical stability, mechanical hardness, reasonable saturation magnetization and high magnetocrystalline anisotropy [1]
It implies that there is a correlation between lattice constant and ionic radius [13], which may be expressed by the empirical equation as: R [ ± FR, where R is the lattice constant for any value ofx (Mn content), [ the lattice constant at x =0 and m is the slope to determine the rate of change of a with x
Three systems of magnetic field adjusting dopant (Mn) doped cobalt ferrite with composition formula Co1-xMnxFe2O4, CoMnxFe2-xO4, and Co1+xMnxFe2-xO4 have been undertaken for analytical study in a theoretical approach

Summary

Introduction

Cobalt ferrites are reported as the best-known examples of the hard ferrite materials because of their excellent chemical stability, mechanical hardness, reasonable saturation magnetization and high magnetocrystalline anisotropy [1]. Intensive researches towards the discovery and development of cobalt ferrite nanoparticles with doped and composite kind have been made them possible to be used in diversified fields of application such as electronic devices, ferrofluids, drug delivery system, magnetic resonance imaging, microwave devices and high-density information storage. These applications are mostly based on magnetic and electrical behaviors and their alteration or tuning, depending on the ionic radii of doped atoms in the host lattice and their particle size. Lattice constants of Co1-xMnxFe2O4, American Journal of Applied Scientific Research 2019; 5(3): 56-61

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