Ultrathin Ternary FeCoNi Alloy Nanoarrays in BaTiO3 Matrix for Room-Temperature Multiferroic and Hyperbolic Metamaterial

• DOI: 10.1021/acs.nanolett.4c02036
• Publication Date: 2024-08-07T11:44:06Z
• Authors: Jijie Huang; Leigang Li; Zedong Hu; Benson Kunhung Tsai; Jialong Huang; Jianan Shen; Yizhi Zhang; James P. Barnard; Jiawei Song; Haiyan Wang

Multifunctional vertically aligned nanocomposite (VAN) thin films exhibit considerable potential in diverse fields. Here, a BaTiO3-FeCoNi alloy (BTO-FCN) system featuring an ultrathin ternary FCN alloy nanopillar array embedded in the BTO matrix has been developed with tailorable nanopillar size and interpillar distance. The magnetic alloy nanopillars combined with a ferroelectric oxide matrix present intriguing multifunctionality and coupling properties. The room-temperature magnetic response proves the soft magnet nature of the BTO-FCN films with magnetic anisotropy has been demonstrated. Furthermore, the anisotropic nature of the dielectric-metal alloy VAN renders it an ideal candidate for hyperbolic metamaterial (HMM), and the epsilon-near-zero (ENZ) wavelength, where the real part of permittivity (ε') turns to negative, can be tailored from ∼700 nm to ∼1050 nm. Lastly, room-temperature multiferroicity has been demonstrated via interfacial coupling between the magnetic nanopillars and ferroelectric matrix.