Magnetoelectric effect and complex impedance analysis of (x)CoFe2O4 + (1-x)Ba0.8Sr0.2TiO3 multiferroics

Magnetoelectric composites of CoFe2O4 (CFO) ferrite and strontium doped BaTiO3 (BSTO) ferroelectric were synthesized by solid state reaction method. X-ray diffraction was used to confirm the presence of constituent phases in the composite. No intermediate peak was observed in the composite other than parent phases. Dense, diphase microstructure of the composite was examined by field emission scanning electron microscope (FESEM). Temperature dependent complex impedance analysis was carried out in order to separate the grain, grain boundary and electrode-electrolyte effect. Analysis of AC impedance data indicates a typical negative temperature coefficient of resistance. The magnetic hysteresis was studied to know the response of CoFe2O4 ferrite to the applied magnetic field. The saturation magnetization was found to decrease with increase in phase fraction of BSTO in the composite. All composites after post calcination in oxygen were electrically and magnetically poled to exhibit significant magnetoelectric effect. A maximum magnetoelectric voltage coefficient of about 0.761 mV/cm. Oe was observed for 15%CoFe2O4 + 85%Ba0.8Sr0.2TiO3 composite at room temperature. (C) 2009 Elsevier B.V. All rights reserved.