Interfacial effects on the structural, optical, and magnetic properties of α-Fe₂O₃@RuO₂ core–shell nanostructures

Abstract Magnetic nanoparticles composed of transition metal oxides have attracted considerable attention owing to their potential applications in information storage, photocatalytic activities, biomedicine, and hyperthermia-based cancer treatment. A key factor underlying these functionalities is the interfacial spin interaction, which governs the magnetic behavior at the nanoscale by tailoring their physical properties. Here, we present the structural, optical, and magnetic characteristics of a bi-magnetic α- Fe 2 O 3 @ RuO 2 core–shell nanostructure composed of spindle-shaped α -Fe 2 O 3 decorated with RuO 2 nanoparticles. Structural and morphological characterizations confirm the coexistence of both phases in the core–shell system. Optical analyses indicate an enhanced absorption capability of the core–shell nanostructures, beneficial for photocatalytic activity. Additionally, the core–shell system was found to exhibit a Morin transition, similar to core α -Fe 2 O 3 . Moreover, our findings also reveal a notable increase in both the coercive field and exchange bias, possibly resulting from the interfacial interaction between the core and shell nanoparticles. This enhancement indicates improved magnetic alignment and unidirectional anisotropy, providing valuable insights into the magnetic properties of core–shell structures and their potential applications in advanced materials.