The role of flash auto-combustion method and Mn doping in improving dielectric and magnetic properties of CoFe_2O_4

摘要

In this work, we prepared Co_(1-x)Mn_xFe_2O_4 (CMFO) ferrites at different levels of doping x-0.0, 0.1,0.3, 0.5 and 0.7 using flash auto-combustion method, aiming to obtain promising results more than CoFe_2O_4 ferrite prepared by other methods. The results show an increase in lattice constant of CMFO with Mn content. In addition, there are many intra-granular pores and significant fusion of the small grains into larger grains. The dielectric properties of CMFO ferrites are enhanced with Mn content. Furthermore, saturation magnetization (M_S) and remanent magnetization (M_r) of CMFO are improved slightly with Mn content up to x= 0.1 and then decrease with higher Mn content. The coercivity (H_C) of CMFO ferrite decreases with Mn content until it reaches minimum value of 971 Oe for level of Mn substitution x = 0.5; on further Mn content (X=0.7), it is observed that H_c increases to 1249 Oe. In comparison to previous works, H_c (x = 0) and M_S and M_r for our sample (x = 0.1) are significantly more than corresponding values obtained for CoFe_2O_4 ferrite prepared by other methods.