Synthesis and characterization of BaFe12O19-CoFe2O4 ferrite composite for high frequency magnetic application

Abstract

Recently, magneto-dielectric ferrite composite ceramics have received much attention for high frequency device applications since they have both magnetic and dielectric properties, as well as high electrical resistivity and good chemical stability [1]. BaFe12O19 (BaM) and CoFe2O4 (CoF) ferrites composites; (BaM)1-x(CoF)x (x= 0, 0.25,0.5, 0.75 and 1) were successfully synthesized by co-precipitation method. The XRD analysis confirms the formation of pure phase BaM ferrite at 800oC and CoF ferrite at 600oC respectively. The XRD analysis of composite ferrite showed the presence of two phase system in the composite indicating its true composite in nature. The composites were sintered at 1100oC/4h. The microstructure of the composite containing 25 mole % CoF ferrite showed most compact structure with less porosity compared to other composites. Among all composites, the 25 mole % of CoF ferrite containing composite has the highest permittivity (14) and permeability (12) due to mainly better densification and lower porosity. Permeability of all the composites is almost stable upto about 1 GHz and magnetic, dielectric losses were low at high frequency range from 100MHz to 1GHz. Magnetization result (Fig. 1) shows that BaM-CoF (3:1) composition has lowest coercivity among all composition indicating a change of hard ferrite behavior into soft magnetic behavior of BaM when composite was formed. These properties suggest that the low-loss (BaM)1-x(CoF)x ferrite composite ceramic is a new kind of multifunctional magneto-dielectric material having potential for high-frequency electromagnetic device applications.