Synthesis and Properties of NiFe2O4 and Ni0.5Zn0.5Fe2O4 Prepared by Auto-combustion Method

Abstract

NiFe2O4 (NF) and Ni0.5Zn0.5Fe2O4 (NZF) powders as a part of multiferroic composites were prepared by auto-combustion method starting from nickel, zinc and iron nitrates. After the process of self-ignition, fine precursor powders were thermally treated at 1000 oC for 1h forming the nickel ferrite and nickel-zinc ferrite powders [1]. XRD analysis proved the formation of well crystallized cubic spinel structure in both ferrites. Particle size distribution measurements showed the existence of agglomerates. SEM micrographs showed the existence of polygonal grains ~ 100-500 nm. The results of powders characterization are presented in the table I. Ceramics materials were obtained by sintering at 1250 oC for 4 h in the tube furnace. XRD analysis showed the formation of well crystalline spinel structure in both materials. Magnetic measurements of ferrites were carried out and presented in Figure 1. Saturation magnetization moment of NF was lower than for NZF and the fields at which saturation occur was almost the same for both ceramics. The coercivity HC (Oe) was higher for the NZF indicating that it is “softer” than NF [2]. Permeability vs. frequency measurements showed that NZF possesses much higher permeability that NF. On the other hand, the NF permeability value keeps constant values in a broader frequency range than NZF ceramics.