Design of spinel ferrite-based nanoheterostructures synthesized by solvothermal approaches

A solvothermal method was developed for the synthesis of bimagnetic spinel ferrite-based core-shell and silver-spinel ferrite flower-like nanoheterostructures (NHs). CoFe2O4, MnFe2O4, and spinel iron oxide (maghemite and magnetite) were prepared by a solvothermal process using ex-situ prepared metal oleates. One sample of MnFe2O4 and three samples of CoFe2O4 were used as seeds for the growth of an isostructural shell of another spinel ferrite (seed-mediated growth). The samples were characterized from the compositional, structural, morphological, and magnetic point of view. The CoFe2O4 core-based core-shell NPs were exploited for magnetic fluid hyperthermia applications. Regarding the second topic, the oleate-based solvothermal method was employed for the synthesis of silver-spinel ferrite NHs, starting from both silver and spinel ferrite NPs seeds. Flower-like NHs having silver core and CoFe2O4, MnFe2O4, or spinel iron oxide petals were successfully prepared using small silver NPs as germs.