Synthesis and multiferroic properties of particulate composites resulting from combined size effects of the magnetic and ferroelectric phases

The effect of grain size was not fully explored in composites containing ferroelectric and magnetic phases including the independent properties of each phase. Aiming to study the dependence of ferroic and multiferroic properties with average grain size in composites this work reports preparation method and electric, magnetic and magnetoelectric properties of particulate composites with distinct combination of grain size of each phase. A new sintering method was applied to prepare a group of samples with distinct configuration of grain size distribution. With this method it was possible to densify ceramics avoiding grain growth using spark plasma sintering. It was observed that the all ferroic and multiferroic properties were correlated with the setup of grain size of each phase in the composite, by example the dependence of magnetic properties with the electric phase grain size. Besides it was noticed that is possible to improve magnetoelectric coefficient by changing grain size of both phase, even inducing the self-biased effect by decreasing the grain size of the ferroelectric phase.