Exchange-spring behavior in BaFe12O19-Ni0.5Zn0.5Fe2O4 nanocomposites synthesized by a combustion method

Exchange-spring systems offer various technological applications. In this study, BaFe12O19-Ni0.5Zn0.5Fe2O4 nanocomposite magnets with single-step hysteresis loops were synthesized through a simple combustion method. Their composition, microstructure, and magnetic properties were also investigated. It was found that the magnetic properties and the mechanisms governing the magnetization of these nanocomposite magnets are strongly influenced by the calcination temperature as well as the molar ratios of the hard and soft phases. The exchange-coupling between the hard and soft magnetic phases was confirmed by the study of Henkel plots and the variation in the magnetic properties could also be explained by the dominant role of exchange and dipolar interactions in the nanocomposites. The study provides a simple but efficient route for the fabrication of exchange-coupled nanocomposite magnets based on ferrites having controllable magnetic properties.