Au-Encapsulated Fe Nanorods in Oxide Matrix with Tunable Magneto-Optic Coupling Properties

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-La_0.5Sr_0.5FeO₃ (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.