Enhanced magnetodielectric effect and optical property of lead-free multiferroic (1 - X)(Bi0.5Na0.5)TiO3/xCoFe 2O4 composites

Abstract

(1 - x)(Bi0.5Na0.5)TiO3/xCoFe 2O4 composites with x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5 were synthesized by solid state reaction method. Presence of distinct ferroelectric (Bi0.5Na0.5)TiO3 and ferrite CoFe 2O4 phases in the prepared composites have been confirmed by the X-ray diffraction analysis and field emission scanning electron micrographs. The variation of dielectric constant with temperature for these prepared composites show an anomaly near antiferroelectric to paraelectric phase transition temperature (∼345 °C) of pure (Bi0.5Na 0.5)TiO3 ceramics. The dielectric constant of the composites at low frequency range decreases with increase in CoFe 2O4 content up to x = 0.3 but increases for x = 0.4 and x = 0.5. The value of remnant magnetization for 10 and 50% CoFe2O 4 are 2 and 14 emu g-1 respectively. The maximum value of magnetocapacitance was found to be ∼4.37% for 50% CoFe2O 4 content. Increase in CoFe2O4 content in composites shifts the optical band gap of (Bi0.5Na 0.5)TiO3 towards lower energy side. © 2014 Elsevier B.V. All rights reserved.