Multiferroic thin films and self-assembled heterostructures via solution-gel chemistry

Abstract

The trend towards miniaturization of electronic devices has enhanced the demand for multifunctional materials, mostly in the form of thin films or nanostructures. Multifferoic materials are interesting candidates for applications in electronics because they combine ferroelectric and ferromagnetic properties resulting in new functionalities when orders are coupled [1,2]. To obtain thin films of the complex oxides, solution-gel chemistry is considered as a flexible and relatively cost-effective method. We synthesized aqueous solutions with different compositions, as precursors for single phase or composite multiferroic materials. Thus, polycrystalline and epitaxial films of BiFeO3 were deposited on different substrates overcoming the issues concerning phase formation and stabilization, secondary phase formation and interaction between film and substrate. Furthermore, flexibility of solution processing is shown by growing self-assembled heterostructures of a two-phase system consisting of ferroelectric (BaTiO3 or BiFeO3) and magnetic (CoFe2O4) phases. A thorough structural and morphological investigation is correlated with the magnetic properties of the obtained films.