Magnetic spinel oxides stand out among magnetostrictive materials for their suitability to be co-processed with high-sensitivity-piezoelectric ferroelectric perovskite oxides to fabricate ceramic composites, which provide magnetoelectricity as a product property of the two piezoresponses. This material technology is being investigated for a range of applications, such as magnetic field sensing, tunable microwave components and power transmission, to name a few. The latter example is a key technology for several bioimplanted medical devices under development for diagnosis and therapeutics. However, current-state-of-the-art materials are based on either NiFe2O4 or CoFe2O4 that are toxic, and medical applications require the development of alternative biocompatible materials.
This work presents a study of the spinel phases across the (Mg, Zn)Fe2O4 system, and of their suitability to be used as magnetostrictive component in magnetoelectric composites. Powdered (1 − x) MgFe2O4- x ZnFe2O4 (x=0, 0.25, 0.5, 0.75, 1) phases with variable particle size across the nanometer and submicron scales were prepared by mechanochemical synthesis, from which ceramic materials with controlled grain growth and adequate for property characterization were obtained by spark plasma sintering.  Electrical, magnetic and magnetostrictive properties were characterised, and their evolution with chemical composition and particle size described. Functionality of the different obtained materials for magnetoelectric composites is analysed