Structure, magnetic and transmission characteristics of the Co substituted Mg ferrites synthesized via a standard ceramic route

Abstract

Co-Mg ferrites, CoxMg1−yFe2−zO4 (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0, 0 < y < 0.34 and 0 < z < 0.67), were synthesized via a standard ceramic route, and the structural, morphological, magnetic properties and transmission parameter of the samples were studied. The thermal behavior of the ground powder was characterized using a differential thermal analysis technique (DTA). The XRD patterns proved the formation of single phase Mg-ferrite in the samples with "x" contents varying from 0.0 to 0.8. The sample with x = 1.0 showed two phases: a spinel Mg-ferrite and a secondary (Co,Mg)O phase. The lattice parameter and crystallite size of the samples increased remarkably by increasing the x content. The SEM images revealed that Co substitution in Mg ferrite at x = 0.2 causes the particle growth, but their growth was not significant until x = 0.8. For x = 1.0, a remarkable particle growth was again observed. A maximum bulk density of 4.94 g/cm3 was obtained for x = 0.8. Magnetic properties of the sintered samples showed an increase in coercive force up to 113 Oe by increasing Co substitution up to x = 1.0. Saturation magnetization reached a maximum value of ~45.40 emu/g at x = 0.8. Studying the microwave transmission behavior of the samples, using a vector network analyzer (VNA), indicated that by increasing Co, the transmission loss was reduced from ~− 15 dB for x = 0.0 to less than − 10 dB for x = 0.8 in the frequency range of 8–12 GHz.