Plasmonic oxide‐metal hybrid nanostructures exhibit unprecedented optical properties because of the nanoscale interactions between the oxide and metal components. Precise control of the geometry and arrangement of optical building blocks is key to tailoring system properties toward various nanophotonic applications. Herein, self‐assembled BaTiO3‐Au vertically aligned nanocomposite thin films with a series of thicknesses are fabricated using a one‐step pulsed laser deposition technique. By reducing the film thickness, the geometry of Au phase is effectively tailored from nanopillars to nanodisks, with the aspect ratio (height/width) varied from ≈4.0 to ≈1.0. The experimental optical spectra and numerical simulation results demonstrate that localized surface plasmon resonance and hyperbolic dispersion wavelength can be effectively tuned in the visible to near‐infrared regime by varying the film thickness due to the change of Au aspect ratio and free electron density. This study demonstrates a feasible approach in tuning the optical responses in hybrid oxide‐metal nanostructures, and opens up enormous possibilities in design and fabrication of novel optical components toward all optical integrated devices.

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Materials with magneto-optic coupling properties are highly coveted for their potential applications ranging from spintronics and optical switches to sensors. In this work, a new, three-phase Au–Fe–La0.5Sr0.5FeO3 (LSFO) hybrid material grown in a vertically aligned nanocomposite (VAN) form has been demonstrated. This three-phase hybrid material combines the strong ferromagnetic properties of Fe and the strong plasmonic properties of Au and the dielectric nature of the LSFO matrix. More interestingly, the immiscible Au and Fe phases form Au-encapsulated Fe nanopillars, embedded in the LSFO matrix. Multifunctionalities including anisotropic optical dielectric properties, plasmonic properties, magnetic anisotropy, and room-temperature magneto-optic Kerr effect coupling are demonstrated. The single-step growth method to grow the immiscible two-metal nanostructures (i.e., Au and Fe) in the complex hybrid material form opens exciting new potential opportunities for future three-phase VAN systems with more versatile metal selections.

Silicon integration of nanoscale metamaterials is a crucial step toward low-cost and scalable optical-based integrated circuits. Here, a self-assembled epitaxial Au–BaTiO3 (Au–BTO) hybrid metamaterial with highly anisotropic optical properties has been integrated on Si substrates. A thin buffer layer stack (<20 nm) of TiN and SrTiO3 (STO) was applied on Si substrates to ensure the epitaxial growth of the Au–BTO hybrid films. Detailed phase composition and microstructural analyses show excellent crystallinity and epitaxial quality of the Au–BTO films. By varying the film growth conditions, the density and dimension of the Au nanopillars can be tuned effectively, leading to highly tailorable optical properties including tunable localized surface plasmon resonance (LSPR) peak and hyperbolic dispersion shift in the visible and near-infrared regimes. The work highlights the feasibility of integrating epitaxial hybrid oxide–metal plasmonic metamaterials on Si toward future complex Si-based integrated photonics.

Metallic nanostructures within ceramic matrices provide a unique platform for integrating magnetic, optical, and electrical properties for device applications. Currently, hurdles still exist for the integration of metallic nanostructures within conventional devices, including the incompatible growth conditions between metals and ceramics and control of the overall physical properties. In this study, we demonstrate the tunability of a one-step growth method to fabricate magnetic and metallic nanostructures embedded within an oxide matrix, La0.5Sr0.5FeO3:Fe, from a composite target using pulsed laser deposition. The metal-ceramic nanocomposite films demonstrate tunable nanostructures and anisotropic magnetic response by varying deposition energy, presenting a mechanism for tuning the physical properties of vertically aligned ferromagnetic metallic nanopillars in an oxide matrix. This study also opens avenues towards the integration of nanoscale, vertical, metallic ferromagnetic contacts for anisotropic magnetic tunneling junctions which may not be easily realized by single-phase thin films.