Structure, morphology and magnetic properties of Mg(x)Zn(1-x)Fe2O4 ferrites prepared by polyol and aqueous co-precipitation methods: a low-toxicity alternative to Ni(x)Zn(1-x)Fe2O4 ferrites

The synthesis and properties of Mg(x)Zn(1-x)Fe2O4 spinel ferrites as a low-toxicity alternative to the technologically significant Ni(x)Zn(1-x)Fe2O4 ferrites are reported. Ferrite nanoparticles have been formed through both the polyol and aqueous co-precipitation methods that can be readily adapted to industrial scale synthesis to satisfy the demand of a variety of commercial applications. The structure, morphology and magnetic properties of Mg(x)Zn(1-x)Fe2O4 were studied as a function of composition and particle size. Scanning electron microscopy images show particles synthesised by the aqueous co-precipitation method possess a broad size distribution (i.e. similar to 80-120 nm) with an average diameter of the order of 100 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-precipitation method possess a narrower size distribution with an average diameter in the 30 nm +/- 5 nm range but are limited to smaller yields of similar to 6 g l(-1). Furthermore, the polyol synthesis method was shown to control average particle size by varying the length of the glycol surfactant chain. Particles prepared by both methods are compared with respect to their phase purity, crystal structure, morphology, magnetic properties and microwave properties.