Metal Oxide Nanocomposites: A Perspective from Strain, Defect, and Interface

Abstract

Complex metal oxides, which show a variety of functional properties such as ferromagnetism, ferroelectricity, multi-ferroelectricity, superconductivity, and ionic conduction, have attracted much attention in the past decades. These exotic physical properties arise from a complex hierarchy of competing interactions among spin, charge, orbital, and lattice degrees of freedom. The development of advanced characterization techniques such as electron microscopy, neutron scattering, synchrotron scattering and imaging, spectroscopy at high magnetic fields, and others has enabled us to study the interactions among these degrees of freedom coupled with strain, defect, and interface Vertically aligned nanocomposite thin films with ordered two phases, grown epitaxially on substrates, have attracted tremendous interest in the past decade. These unique nanostructured composite thin films with large vertical interfacial area, controllable vertical lattice strain, and defects provide an intriguing playground, allowing for the manipulation of a variety of functional properties of the materials via the interplay among strain, defect, and interface. This field has evolved from basic growth and characterization to functionality tuning as well as potential applications in energy conversion and information technology. Here, the remarkable progress achieved in vertically aligned nanocomposite thin films from a perspective of tuning functionalities through control of strain, defect, and interface is summarized. Thin FilmsThe ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adma.201803241. 12 11 12where c 11 and c 12 are elastic moduli of the film material. Epitaxial strain gradually changes with film thickness in perovskite manganites. Figure 3 shows reciprocal space mapping or RSM (103) of La 0.7 Ca 0.3 MnO 3 (LCMO) films on STO (001) substrates. It captures the gradual strain relaxation process with increasing film thickness in manganite thin films. When the film is very thin, the interface is coherent with

Symbiotic, low-temperature, and scalable synthesis of bi-magnetic complex oxide nanocomposites

“…[7][8][9][10][11][12][13] More importantly, this family of oxides is interesting not only from the point of fundamental studies, but also due to potential applications in different areas of technology. 14,15 In the quest for new systems with tunable properties, an alternative route that is being increasingly explored in recent years is to make nanocomposites of functional oxides, 16 where the properties of the individual components can be modied by an appropriate choice of the two phases. Nanocomposites are essentially different from single-phase materials, and offer greater exibility for obtaining custom-made properties by combining the properties of the two parent phases.…”

Atomic‐Scale Study of Metal–Oxide Interfaces and Magnetoelastic Coupling in Self‐Assembled Epitaxial Vertically Aligned Magnetic Nanocomposites

“…The large interface/volume ratio is a salient feature of the VAN nanoarchitecture and the vertical interface between the pillars and the surrounding matrix plays a prominent role in determining the final functionality of the nanocomposite. For example, the vertical interface can provide additional conduction channels in ionic conductors; the photocarrier transport can be more efficient due to the Schottky junctions around metallic pillars embedded in a semiconducting matrix; efficient magnetoelastic coupling through epitaxial strain is intimately related to the structure of the vertical interface …”

Role of Interlayer in 3D Vertically Aligned Nanocomposite Frameworks with Tunable Magnetotransport Properties

“…[ 6–12 ] Among all the two‐phase nanocomposite designs, vertically aligned nanocomposites (VANs) offer high‐density vertically aligned interfaces, strain coupling, and strong anisotropic physical properties and have thus attracted great attention. [ 3,13–20 ]…”