Strain, magnetic anisotropy, and composition modulation in hybrid metal–oxide vertically assembled nanocomposites

Self-assembled vertically aligned nanocomposites (VANs) have recently emerged as a novel playground for strain engineering of physical properties in nanostructures. In contrast to thin films obtained by classical planar heteroepitaxy, VANs consist of two (or more) intertwined phases, coupled along vertical interfaces. Their unique nanoarchitecture, which can be tuned by choosing appropriate growth conditions, results in deformations that cannot be easily attained in traditional flat geometries. In this article, we show how nanometer-sized acicular inclusions of magnetic 3d metals in various oxide host matrices can be obtained via sequential pulsed laser deposition. We discuss the distinct sources of magnetic anisotropy in such metal–oxide VANs and demonstrate how to use strain to accurately control the magnetic properties of the nanocomposites. We finally present possible extensions of this approach to more than one embedded metallic phase and sketch some of the remaining challenges that must be overcome to create novel functional nanoarchitectures.