Synthesis and Characterization of x BaTiOs - (1-x) NiFezO+ Composites

Abstract

Multiferroic composites with the general formula x BaTiO3-(l-x) NiFezO+ (x = 0.5, 0.7, 0,8) were prepared by mixing chemically obtained powders of nickel ferrite and barium titanate. NiFezO+ powder was prepared by auto combustion method stafting from nickel and iron nitrates. After - 4 h solvent was removed and during the process of self-ignition fine powder was obtained. Thermal treatment was peformed at 1000 oC for t h and the nickel ferrite powder (NF) was formed. Barium titanate (BT) powder was prepared by a polymeric precursor method. Barium and titanium citrate solutions were peformed using barium acetate and titanium-isopropoxide. The .obtained citrates were mixed and heated at 140 oC for - 5 h. Thermal treatments was further performed at 250 ocl1 h and 300 ocl4h, and after that in the temperature range 350-800 oC for 4h barium titanate nanopowder was formed [1].Composites (BT-NF) with the general formula x BaTiO3 - (1-x) NiFe2O4 were prepared by mixing obtained powders of nickel ferrite and barium titanate in planetary ball mill for 24h. Powders were pressed and sintered at 1170 oC for 4 h. X-ray measurements confirmed the presence of NF and BT phases. The microstructure of the ceramics showed formation of polygonal grains, (Fig.1, right). Magnetic measurements of composite materials were carried (Fig.l, left). Saturation magnetization moment of composite materials decrease with barium titanate amount and the fields at which saturation occur increase with BT content. The coercivity Hc (Oe) increases with barium titanate concentration in obtained multiferroic material.