Microstructural effects of chemical island templating in patterned matrix-pillar oxide nanocomposites

Abstract

The ability to pattern the location of pillars in epitaxial matrix -pillar nanocomposites is a key challenge to develop future technologies using these intriguing materials. One such model system employs a ferrimagnetic CoFe2O4 (CFO) pillar embedded in a ferroelectric BiFeO3 (BFO) matrix, which has been proposed as a possible memory or logic system. These composites self-assemble spontaneousl y with pillars forming through nucleation at a random location when grown via physical vapor deposition. Recent results have shown that if an island of the pillar material is pre-patterned on the substrate, it is possible to control the nucleation process and determine the locations where pillars form. In this work, we employ electron microscopy and xray diffraction to examine the chemical composition and microstructure of patterned CFO -BFO nanocomposites. Cross-sectional transmission electron microscopy is used to examine the nucleation effects at the interface between the template island and resulting pillar. Evidence of grain boundaries and lattice tilting in the templated pillars is also presented and attributed to the microstructure of the seed island.

Hierarchically Engineered Manganite Thin Films with a Wide-Temperature-Range Colossal Magnetoresistance Response

“…In addition, such hierarchically engineered nanostructures might have great benefits in lowering unit-to-unit performance variation in nanodevices with grain-boundary effects involved. To be specific, using prepattern technologies, − the seed layer can be structured into an ordered array with a controllable density of nanocrystals. After a subsequent deposition of the functional oxides, hierarchical films with a local variation of the grain boundary density might be engineered.…”

Spintronics technology: past, present and future

“…Patterning processes have been developed to template the positions of CFO pillars in the epitaxial CFO-BFO nanocomposites by several groups. [79][80][81] The AFM image of such a patterned nanocomposite with a square array of CFO pillars with a pitch of 100 nm is shown in Fig. 8.…”