Solvothermal Clustering of Magnetic Spinel Ferrite Nanocrystals: A Raman Perspective

The one-pot formation of colloidal nanocrystal clusters has recently gained attention because of the new set of phenomena with which such secondary structures are endowed. Nevertheless, given the number of complex processes at play, the correct interpretation of the chemical mechanisms behind the formation of such structures remains a particularly difficult task. In this work, magnetic colloidal nanocrystal clusters with a spinel structure are thoroughly characterized by means of transmission electron microscopy, X-ray diffraction, magnetic measurements, and Raman spectroscopy. The combination of these techniques results in a means of unraveling the structure of the poorly crystalline intermediates and complex products formed throughout the process. Our results suggest that the chemical and crystallographic transformations that the nanostructures undergo at the different stages of the reaction are strongly related to the final morphology of the secondary superstructures obtained, which, in parallel, help to improve the magnetic properties required in their specific final applications.