Multiferroic (NiZn) Fe2O4–BaTiO3 composites prepared from nanopowders by auto-combustion method

Nickel zinc ferrite (NZF) and barium titanate (BT) were prepared by auto-combustion synthesis as an effective, simple and rapid method. Multiferroic composites with the general formula yNi1−xZnxFe2O4−(1−y)BT (x=0.3, 0.5, 0.7, y=0.5) were prepared by mixing NZF and BT powders in a liquid medium in the ball mill. The FEG micrographs indicated the primary particle size less than 100 nm for both, barium titanate and nickel zinc ferrite phases. X-ray analysis and Raman spectroscopy indicated the formation of well crystallized structure of NZF and BT phase in the composite powders and ceramics, with a small contribution of the secondary phase. The homogenous phase distribution in obtained composites was also confirmed. Impedance spectroscopy measurements were carried out in order to investigate the electrical resistivity of materials, showing that grain boundaries have greater impact on the total resistivity than grains. Saturation magnetization and remnant magnetization continuously decrease with barium titanate phase increase.