Structural Engineering and Site-specific Characterization of Multifunctional Oxide Nanostructures

Patterning of multifunctional oxides into miniaturized, spatially confined structures may change the manner in which the materials interact mechanically with neighboring architectures and induce novel, interesting phenomena or superior functional performances. Researchers at the Northwestern University MRSEC have fabricated high quality, epitaxial magnetic oxide nanostructures that are clamped by the underlying substrate. The nanostructure in return modifies the strain field in the substrate around itself, which can be directly visualized at high resolution with the aid of x-ray microbeam technique. The structural engineering strategy and the site-specific study of the strain field will help achieve in-depth understanding towards the influence of downsizing on the behavior of oxide materials.

(a): SEM image of an 40nm-thick epitaxial CoFe₂O₄ line pattern on (001) MgO single crystal substrate fabricated via VP-soft-eBL. The arrow in the left-bottom corner indicates the <100> direction of the substrate. (b) and (c): x-ray microdiffraction intensity maps of MgO substrate showing the strain contour on both sides of the CoFe₂O₄ line (figure (b)) and that at the end of the line (figure (c)).