Formation of Nanocrystalline Transition‐Metal Ferrites inside a Silica Matrix

Abstract

Nanocrystalline transition‐metal ferrites were synthesized inside an amorphous silica matrix by the sol–gel method. The formation of spinel ferrites began above 400°C, giving fine particles of about 10 nm at 800°C. This is associated with a specific role of the silica matrix, which facilitates the diffusion of the reacting cations, enhancing the ferrite formation. Above 1000°C the MnFe 2 O 4 and CuFe 2 O 4 nanoparticles lost their fine nature. The dried gels and crystalline materials were characterized by X‐ray diffraction, thermal, FTIR, and BET analyses as well as by high‐resolution scanning transmission electron microscopy.