Effects of the chemical composition of the magnetostrictive phase on the dielectric and magnetoelectric properties of cobalt ferrite–barium titanate composites

Magnetostrictive–piezoelectric composites of CoFe2O4–BaTiO3 and CoMn0.2Fe1.8O4–BaTiO3 were obtained with standard solid-state ceramic processing. X-ray diffraction (XRD) analysis revealed the presence of the spinel and perovskite phase without the appearance of the residual phase. The influence of the phase content on the dielectric constant, loss tangent, magnetization, magnetostriction and magnetoelectric signal was studied, and the results were correlated with the microstructure and the amount of ferrite. The magnetoelectric response of the composite indicated that the substitution of iron ions for manganese ions decreased the dielectric loss and improved the magnetoelectric signal of the composite samples.

► CoMn0.2Fe1.8O4–BaTiO3 as magnetoelectric composites.
► Dielectric loss decreases as compared with CoFe2O4–BaTiO3 composites.
► Magnetostrictive properties are not altered by the substitution of a small amount of iron with manganese ions.
► A small increase of the magnetoelectric signal is observed for CoMn0.2Fe1.8O4–BaTiO3 as compared with CoFe2O4–BaTiO3.