Nanocrystalline Ferrites with Spinel Structure for Various Functional Applications

Recently, nanosized ferrites with spinel structure have been actively discussed as possible magnetically controlled catalysts, sorbents, and biomedical materials. For the large-scale practical use of ferrites, it is necessary to find simple, reproducible, and cost-effective methods that allow one to control the characteristics of nanosized ferrites with spinel structure to obtain samples with a large number of active centers for catalysis and sorption, low toxicity for biomedical applications, and good magnetic properties required to control such materials by an external magnetic field. This review summarizes the results of scientific studies (predominantly over the last 5–10 years) focused on different methods of synthesis of nanosized ferrites with spinel structure and composite materials, and considers approaches to control their catalytic, sorption, and magnetic characteristics and prospects of their application as magnetically sensitive catalysts (Fenton-like processes), sorbents (extraction of heavy metals, separation of ions, separation of valuable metals), and materials for drug delivery, hyperthermia, and MRI contrast.