The static magnetic properties of composites with orientational anisotropy: Experiment, theory and computer simulation

The properties and behavior of composite materials based on superparamagnetic nanoparticles with an ordered orientational structure of magnetic anisotropy axes are of scientific and applied interest. At present, there is no clear picture of the physical properties of such materials. This paper presents a comprehensive study of the problems of the formation and properties of magneto-textured materials. The study provides a comparative analysis of the obtained empirical material with computer simulation data and results from a developed theoretical model. In particular, the dependence of the composite material’s static magnetic properties on the values of the magnetic field in which the sample was hardened and the measuring magnetic field, as well as on the angle between the directions of these fields, is demonstrated. The correlation of these material properties with the microstructural state, specifically with the orientational distribution of the magnetic anisotropy axes of the nanoparticles, is shown. The material’s equilibrium orientational texture as a function of its preparation conditions is described. The role of different size fractions of nanoparticles and their contribution to the resulting material behavior is demonstrated. The results of the study make it possible to form a complete picture of the phenomena under consideration, as well as to determine the optimal synthesis conditions and to predict the ways of obtaining magneto-textured materials with desired properties.