Study of structural characteristics of Ni-Zn-Co ferrospinels

Currently, in the modern scientific literature there is an increased interest in ferrites of all types. Among them, a special place is occupied by Ni-Zn ferrite with a spinel structure. It is known that the functional properties of ferrites can be significantly changed by partial or complete replacement of the cations of the initial matrix with other cations differing in magnetic moment and size. Such a change in the structure makes it possible to effectively vary the properties of ferrites, i.e. to provide "tuning" of the material for the required properties. An analysis of the literature in this direction has shown that the cobalt ion Co2+ is an effective substitute cation. In this study we are dealing with the Ni-Zn ferrites of variable composition, with the fixed content x (Co) = 0.1. The general formula is: Co0.1Zn0.9-xNixFe2O4, (where x = 0; 0.3; 0.6; 0.9). The aim of the presented work is to synthesize samples, as well as to study their density and porosity, which in turn have a direct effect on the performance properties of ceramic ferrites. The synthesis of the samples was carried out by the solid-phase reaction method, using a high-temperature furnace in an air atmosphere. Previous studies have made it possible to identify a set of optimal physicochemical conditions under which the initial charge ferritization occurs. The initial components for preparing the charge included oxides. X-ray phase analysis and X-ray structural analysis, electron microscopy and energy dispersive X-ray spectroscopy were used as research methods. As a result of X-ray phase analysis, it has been revealed that the obtained samples are monophasic and belong to spinels of the AFe2O4 type (where element A = Ni, Zn, Co). The study of the surface morphology of the samples has revealed the presence of many crystallites of various sizes, the natural faceting of which corresponds to crystallites with a cubic syngony. Investigations of the true and X-ray density of the obtained samples have been carried out. The dependence of the influence of the substitution value x (Ni) on the porosity (density), as well as on the parameters of the elementary crystal lattice, has been determined.