Dielectric and magnetoelectric characterization of CoFe2O4/Sr0.5Ba0.5Nb2O6 composites

Magnetoelectric composites were created through incorporating dispersed CoFe2O4 ferromagnetic grains into a Sr0.5Ba0.5Nb2O6 relaxor ferroelectric matrix. The two phases are chemically compatible and coexist in the dense, sintered composites. Unlike other relaxors, the Sr0.5Ba0.5Nb2O6-containing composites can be electrically poled. The apparent dielectric constant is enhanced by the conductivity in the ferrite phase and the space charge at the phase interface. A significant magnetoelectric effect was observed in all compositions investigated, with a maximum dE/dH value of 24.8 mV/cm/Oe obtained for 0.4CoFe(2)O(4)/0.6Sr(0.5)Ba(0.5)Nb(2)O(6), which is much greater than that of magnetoelectric compounds and solid solutions. These results demonstrate that the Pb-free (Sr,Ba)Nb2O6 relaxor can be advantageously used as the matrix for ferromagnetic/ferroelectric composites in the future development of magnetoelectric materials. (C) 2004 American Institute of Physics.