Structure, morphology and magnetic properties ofMg(x) Zn(1 − x)Fe2O4 ferrites prepared by polyol and aqueous co-precipitation methods: a low-toxicity alternative toNi(x)Zn(1 − x)Fe2O4 ferrites

Abstract

The synthesis and properties ofMg(x)Zn(1 − x)Fe2O4 spinel ferrites as a low-toxicity alternative to the technologically significantNi(x)Zn(1 − x)Fe2O4 ferrites are reported. Ferrite nanoparticles have been formed through boththe polyol and aqueous co-precipitation methods that can be readilyadapted to industrial scale synthesis to satisfy the demand of a variety ofcommercial applications. The structure, morphology and magnetic properties ofMg(x)Zn(1 − x)Fe2O4 were studied as a function of composition and particle size. Scanning electron microscopy images showparticles synthesised by the aqueous co-precipitation method possess a broad size distribution (i.e. ∼ 80–120 nm) with an average diameter of the order of100 nm ± 20 nm and could be produced in high process yields of up to 25 g l − 1. In contrast, particles synthesised by the polyol-based co-precipitationmethod possess a narrower size distribution with an average diameter in the30 nm ± 5 nm range but are limited to smaller yields of ∼ 6 g l − 1. Furthermore, the polyol synthesis method was shown to control average particle size byvarying the length of the glycol surfactant chain. Particles prepared by both methods arecompared with respect to their phase purity, crystal structure, morphology, magneticproperties and microwave properties.