Structural, thermal and magnetic investigations of cobalt ferrite doped with Zn2+ and Cd2+ synthesized by auto combustion method

Abstract The nanoparticles of Cobalt-ferrite (CoFe 2 O 4 ), CoZnFe 2 O 4 and CoCdFe 2 O 4 have been synthesized by Auto-combustion method. In this method, nitrates of Co, Fe, Zn and Cd were used as the starting materials, while citric acid has been used as a fuel for the preparation of the samples of CoFe 2 O 4 , Co 0.9 Zn 0.1 Fe 2 O 4 and Co 0.9 Cd 0.1 Fe 2 O 4 . Further, the effect of Zn 2+ and Cd 2+ doping on the structural, thermal and magnetic properties of Cobalt-Ferrite (CoFe 2 O 4 ) were also investigated as a useful data. Thermal decomposition is confirmed by fast weight loss nearly up to 580.0 °C due to removal of hydroxyl group and after that weight loss has been observed almost negligible up to 1000 °C from the analysis of the TGA plot. In powder XRD results, pure cubic spinel structure of all the composition has been found. With the help of W-H method using XRD data, the crystallite size has been found to be lying in the range from 46.20 nm to 53.30 nm and strain values are obtained from −0.0003 to 0.0008. The FTIR spectra confirmed the presence of M O bond and ferrite in our prepared samples. It may be mentioned on the basis of analysis of results for particle size by two XRD and TEM methods which indicate about the formation of nano materials and doping of cobalt ferrites. Moreover, TEM results have also indicated the presence of nano-sized spherical shape of prepared particles with agglomeration. From analysis of VSM results, the obtained values of coercivity (H c ) have been found for these ferrites between 263.45 Oe and 1408.93 Oe. By the substitution of cobalt magnetic ions with Zn 2+ and Cd 2+ , it is possible to tune the magnetic properties of cobalt ferrite as a promising material for various technological applications.