Multialloy Au-Co-Pd Nanopillars-in-Oxide Hybrid Metamaterials with Tunable Optical and Magnetic Properties

Vertically aligned nanocomposite (VAN) thin films have attracted extensive research interests in recent years owing to their unique structure anisotropy and broad integration compatibility with versatile material systems, which open enormous possibilities in the applications of electronic and photonic devices. In this article, to further expand the materials selection in oxide-metal alloys VAN structure, self-assembled BaTiO₃ (BTO): (Au-Co-Pd) and BTO: (Au-Pd) nanocomposite films are integrated using a simplified oxide-metal strips deposition method via pulsed laser deposition (PLD). Microstructural characterization results confirm the epitaxial film quality and vertically grown Au-Co-Pd and Au-Pd alloyed nanopillars in both nanocomposite films, where the elemental segregation of Au, Co, and Pd is primarily due to the differences in their surface energies. Both experimental and simulated optical data show the highly tailorable optical properties of the hybrid films such as localized surface plasmon resonance and hyperbolic dispersion wavelength shifts in the visible to near-infrared wavelength region. The successful integration of multiple metal elements via the one-step oxide-metal strips method in PLD demonstrates the wide feasibility of integrating diverse materials systems into VAN structure toward multifunctional property coupling for electronic, photonic, and energy devices applications.