Cation substitution in hexagonal ferrites: A unified perspective on structure, magnetic anisotropy, and functional performance

Hexagonal ferrites are important ferrimagnetic materials for electromagnetic applications due to their tunable magnetic anisotropy and spin structure. Their properties are governed by cation distribution across nonequivalent crystallographic sites, which regulates super-exchange interactions and magnetic stability. This review critically evaluates recent progress in cation substitution engineering across hexaferrite families (M-, U-, Y-, Z-, X-, and W-type), emphasizing how dopant chemistry and site occupancy govern magnetic parameters. The analysis highlights both performance enhancement mechanisms and intrinsic trade-offs. Despite extensive studies, a unified structure–property framework for cation substitution across hexaferrite systems is still lacking, with most reports remaining fragmented and composition-specific. This review addresses this limitation by establishing a cross-family perspective on cation substitution in hexagonal ferrites, linking atomic-scale dopant distribution to macroscopic magnetic behavior. Future research should focus on integrating site-selective doping strategies with quantitative structure–property relationships and predictive modeling approaches to enable rational and scalable design of hexagonal ferrites.