Structural, dielectric, magnetic, magnetodielectric and impedance spectroscopic studies of multiferroic BiFeO3-BaTiO3 ceramics

Polycrystalline (1-x)BiFeO3-xBaTiO(3) (x = 0.00, 0.10, 0.20 and 0.30) ceramics have been prepared via mixed oxide route. The effect of BaTiO3 substitution on the dielectric, ferroelectric and magnetic properties of the BiFeO3 multiferroic perovskite was studied. From XRD analysis it revealed that BaTiO3 substitution does not affect the crystal structure of the (1-x)BiFeO3-xBaTiO(3) system up to x = 0.30. Improved dielectric properties were observed in the prepared system. An anomaly in the dielectric constant (epsilon) was observed in the vicinity of the antiferromagnetic transition temperature. Experimental results suggest that in the (1-x)BiFeO3-xBaTiO(3) system, the increase of BaTiO3 concentration leads to the effective suppression of the spiral spin structure of BiFeO3, resulting in the appearance of net magnetization. The dependence of dielectric constant and loss tangent on the magnetic field is a evidence of magnetoelectric coupling in (1-x)BiFeO3-xBaTiO(3) system. The impedance analysis suggests the presence of a temperature dependent electrical relaxation process in the material, which is almost similar for all the concentrations in the present studies. The electrical conductivity has been observed to increase with rise in temperature showing a typical negative temperature coefficient of the resistance (NTCR) behaviors analogous to a semiconductor and suggests a non-Debye type of electrical relaxation. (c) 2011 Elsevier B.V. All rights reserved.