Hierarchical magnetic yolk–shell microspheres with mixed barium silicate and barium titanium oxide shells for microwave absorption enhancement

A facile “hydrothermal-assisted crystallization” route for the synthesis of hierarchical magnetic yolk–shell microspheres with mixed barium silicate and barium titanium oxide shells has been developed. Various yolk–shell microspheres with different shell thicknesses and core sizes have been successfully synthesized by controlling the synthetic parameters. The as-synthesized yolk–shell microspheres possess high magnetization, tailored shells, large specific surface area and high porosity, and are demonstrated to be attractive candidate materials for microwave absorption enhancement. Moreover, a possible formation mechanism based on the sacrificial-templating crystallization, dissolution–precipitation and in situ transformation processes is proposed.