Study of Structural and Magnetic Properties of Spinel Zn Doped Cobalt Ferrites

Abstract

Herein, the spinel Co 1-x Zn x Fe 2 O 4 (x = 0.0, 0.2, 0.4 and 0.6) powder samples have been prepared by the solid-state reaction method. We have carried out the measurements of crystal structure, element analysis, material characterization, magnetic property and Curie temperature using the X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometer, and the first-principles calculations within the framework of the density functional theory (DFT). The EDS measurement indicates that the Co 1-x Zn x Fe 2 O 4 powder samples have been successfully synthesized and exhibited the cubic spinel structures. Both the lattice constant and crystallite size increase with the Zn concentration due to the larger ionic radius of Zn 2+ ion than the Co 2+ ion. The concentration ratio of the Co 2+ and Co 3+ ions can be predicted by the distribution of cations between the A and B sites by the XPS measurement. For the magnetic properties, the residual magnetization, coercivity and Curie temperature decrease monotonically as the Zn concentration increases, while the saturation magnetization initially increases and then decreases at the room temperature. For the Co 0.8 Zn 0.2 Fe 2 O 4 sample, the magnetic saturation reaches the maximum value of 62.98 Am 2 kg -1 , due to a large amount of the Co 3+ ions. The adequate replacement of Zn ion for the Co site can improve the magnetic properties of spinel Co 1-x Zn x Fe 2 O 4 powders, and effectively regulates the Curie temperature.