Dielectric and magnetic properties of xCoFe2O4–(1 − x)[0.5Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3] composites

Abstract

xCoFe2O4–(1−x)(0.5Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3) composites with x=0.1, 0.2, 0.3 and 0.4 have been synthesized by solid state reaction method. X-ray diffraction analysis and field emission secondary electron microscopy have been used for structural and morphological analysis, respectively. The spinel CoFe2O4 and perovskite 0.5Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3 phase could be identified in the composites. Two anomalies in dielectric constant have been identified: first one is close to ferroelectric to paraelectric phase transition of 0.5Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3 ceramic and the other lies near the magnetic transition temperature of CoFe2O4. There is an increase in magnetocapacitance and saturation magnetization of the composites at room temperature with increase in CoFe2O4 content. The magnetoelectric coupling coefficient (γ) was approximated by Δϵ∼γM2 relation. The optical band gap energy of the composites decreases with increase in CoFe2O4 content.