Hierarchical Templating of a BiFeO₃–CoFe₂O₄ Multiferroic Nanocomposite by a Triblock Terpolymer Film

Abstract

A process route to fabricate templated BiFeO₃/CoFe₂O₄ (BFO/CFO) vertical nanocomposites is presented in which the self-assembly of the BFO/CFO is guided using a self-assembled triblock terpolymer. A linear triblock terpolymer was selected instead of a diblock copolymer in order to produce a square-symmetry template, which had a period of 44 nm. The triblock terpolymer pattern was transferred to a (001) Nb:SrTiO₃ substrate to produce pits that formed preferential sites for the nucleation of CFO crystals, in contrast to the BFO, which wetted the flat regions of the substrate. The crystallographic orientation and magnetic properties of the templated BFO/CFO were characterized