Grain coarsening and its effects on the properties of magnetoelectric 0.675(Pb(Mg1/3Nb2/3)O3)-0.325PbTiO2/CoFe2O4 particulate composites

In this work, the influence of the grain coarsening on dielectric, magnetic and magnetoelectric properties of particulate composites constituted by (0.8)0.675(Pb(Mg1/3Nb2/3)O3)-0.325PbTiO2 - (0.2)CoFe2O4 (or PMNPT-CFO) and prepared by solid-state reaction method are presented. The increase of average grain size enhances the tetragonal distortion at the structure of the PMNPT matrix due to control of internal stress of the ferroelectric phase. As consequence, the values of the ε′, g33 and αME coefficients reached maximum (ε′ = 25,000, g33 = 53 × 10−4 Vm/N and αME = 14.5 mV/cm Oe) as result of the enhancement of domain structure in the composites. An increase of aprox. 65% in the magnetoeletric coefficient was achieved controlling the microstructure of composites indicating that the magnetoelectric properties in these composites systems could be enhanced by the correct control of the grain coarsening between the phases in particulate composites.