Misorientation Control and Functionality Design of Nanopillars in Self-Assembled Perovskite-Spinel Heteroepitaxial Nanostructures

In this study, advanced control of crystallographic orientations and magnetic properties of self-assembled nanostructures via rational selections of substrates is demonstrated. We show that in the perovskite spinel BiFeO3-CoFe2O4 model system the crystal orientation of self-assembled CoFe2O4 nanopillars can be tuned among (001), (011), and (111), while that of the BiFeO3 matrix is fixed in (001). Moreover, the resultant CoFe2O4 nanopIllars appear in various shapes: pyramid, roof, and triangular platform, respectively. The tunable nanostructures through this approach enable the control of material functionality such as the magnetic anisotropy of CoFe2O4. This study opens a new pathway for the engineering of self-assembled heteroepitaxial nanostructures.