Structural, Magnetic, and Dielectric Properties of Ultrafine Nickel-Substituted Cobalt Ferrite-Reduced Graphene Oxide Nanocomposites

N Ambikeswari,S Manivannan

doi:10.1007/s11664-021-09130-0

Abstract

Nickel-substituted cobalt ferrite–reduced graphene oxide (NCF-RGO) composite was synthesized using a facile one-pot chemical coprecipitation method. The addition of graphene oxide (GO) leads to the decrease in the size of NCF nanoparticles (< 10 nm) present in the nanocomposite, which plays role in controlling their magnetic and dielectric properties. Nickel with a lower ionic radius compared to cobalt, and its substitution in the composite along with the incorporation of GO, exhibits superparamagnetic properties in the blend. A large magnetization of 51.63 emu/g and a high dielectric constant of 3.92 × 106 (at 100 Hz) were also determined for the nanocomposite. High charge-storing capability and tunable magnetization have been developed in this work. Thus the NCF-RGO nanocomposite finds potential application in flexible magnetic storage devices. Nickel-substituted cobalt ferrite-reduced graphene oxide (NCF-RGO) composite was synthesized via the chemical coprecipitation method. A superparamagnetic transition was exhibited by the composite, with an enhanced dielectric constant of 3.92 × 106 at 100 Hz.

Highlights

Dielectric deals with materials having desirable permittivity; low loss and good processability find their unique applications in high k - gate dielectrics and data storage devices
In general exhibit high magnetic property with large magnetisation and likely to get modifed with the grafting of suitable substitutions
The spinel ferrite structure can be described by Fd 3 m centro-symmetric space group and factor group analysis predicts the existence of five Raman active internal modes: A1g + Eg + 3T2g [17]

Summary

Introduction

Dielectric deals with materials having desirable permittivity; low loss and good processability find their unique applications in high k - gate dielectrics and data storage devices. The substantial lattice vibrations displace the intrinsic dipole moment and results in dielectric permittivity. Several factors such as morphology, contribution of grain boundaries, and the internal material layers are said to be the deciding factors responsible for the dielectric properties. Transition metal ferrites, MFe2O4 (M = Co, Ni, Mn, Zn, Fe, etc.,) crystallizes in an inverse spinel structure with a general formula for the ion distribution A3+[B2+B3+]O42− where A denotes tetrahedral cation sites and B denotes octahedral cation sites [2]. The dielectric properties of ferrites strongly dependent on the distribution of cations, the required conditions for its preparations and the substitution of various transition metals [2]

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