The structural, electrical and magnetic properties of perovskite (1-x)Ba(Fe1/2Nb1/2)O3-xbatio3 ceramics

Abstract

Lead-free pseudo-binary compounds (1-x)Ba(Fe1/2Nb1/2)O3-xBaTiO3; (0 ≤ x ≤ 1) have been synthesized at 1200oC using conventional ceramic technique and characterized by X-ray diffraction, scanning electron microscopy, dielectric and vibration sample magnetometer studies. The crystal structure of the compounds is found to be monoclinic with the space group P2/m except for BaTiO3 for which it is tetragonal (P4/mmm). The incorporation of BaTiO3 significantly reduces the dielectric loss and improve the frequency and temperature stability of the dielectric properties of Ba(Fe1/2Nb1/2)O3. Compound 0.25Ba(Fe1/2Nb1/2)O3-0.75BaTiO3 exhibited a low value of temperature coefficient of capacitance (< ±3%) in the working temperature range (up to +85oC), room temperature dielectric constant equal to 282 and low loss tangent (~10-2) which meets the specifications for "Z5D" of Class II dielectrics of Electronic Industries Association. Hence, this composition might be a suitable candidate for capacitor applications. Besides, magnetic studies indicated the possibility of magneto-electric coupling in the system. © 2014 VBRI press.