Hybrid Spinel Iron Oxide Nanoarchitecture Combining Crystalline and Amorphous Parent Material

When preparing nanostructured magnetic materials, the presence of an amorphous component is often considered a weakness of the synthesis method and a waste of material. This stems because the amorphous fraction is often pictured as a “dead” magnetic component, showing little to no contribution to the magnetic properties, for example, saturation magnetization. For this reason, additional steps are employed after the main synthesis process to reduce or isolate and remove the amorphous phase from the “optimal” crystalline product. Here, we propose a hybrid-structured nanoarchitecture that combines crystalline cobalt ferrite and the amorphous parent material. The latter contributes partially to the total magnetic moment but exhibits a magnetic anisotropy much larger than the crystalline bulk parent material. With the information obtained from an in-depth structural and magnetic characterization, a micromagnetic model is created, allowing identifying the contribution of each component elucidating the active role of the amorphous phase. The extremely low cost, minimal complexity, and high yield of the synthesis process make this hybrid design of large interest for technological applications.