Chapter 2: Synthetic Strategies to Improve the Magnetic Properties of Exchange-coupled Nanoheterostructures Check Access

The development of advanced synthetic strategies to produce novel materials with improved or peculiar magnetic properties has been the focus of intense research in the last decade due to their applications in fundamental science and for the tremendous impact these features might have in several technological fields, ranging from biomedicine to the rare-earth-free permanent magnets. In this chapter, three promising strategies aimed at enhancing the performance of quasi-zero-dimensional conventional iron-based spinel ferrites are reported. In the first part, hybrid nanocomposites (exchange-spring magnets) obtained by a two-step, one-pot method are discussed, highlighting the key role of the chosen method in obtaining effective exchange coupling through the interface of hard and soft magnetic phases. In addition, exchange-coupledantiferromagnetic@ferr(i)magnetic nanoparticles doped with several divalent cations (Co^(II) and Ni^(II)) are explored. Interestingly, the combination of the coupling of magnetic components endowed with complementary properties and their double doping can lead to room-temperature exchange bias magnets with high intrinsic magnetic anisotropy. On the other hand, defect engineering has recently been proposed as an effective approach for inducing magnetic features, such as exchange bias, in standard spinel ferrites, which cannot be otherwise observed when the same nanomaterials are obtained by standard techniques, expanding their potential applications in various fields.