LiNbO₃ and ZnO-Ni multilayer thin films as hybrid metamaterials towards tunable properties

Hybrid metamaterials (HMMs) are artificially designed materials made with two or more materials and present optical, magnetic, and mechanical responses that can be tailored. They have attracted great interest in various applications including advanced photonic and acoustic devices. HMMs have been demonstrated in the form of multilayer, particles in matrix, vertically aligned nanocomposites (VANs), and other morphologies. In this work, multilayer and VAN morphologies are integrated as complex HMMs by growing ZnO-Ni VAN and lithium niobate (LiNbO₃, LNO) multilayer structures in either bi-layer stacks or multilayer stacks. The complex hybrid metamaterial system couples tailorable ferromagnetic and optical properties of ZnO-Ni VAN with ferroelectric LNO. The number of layers, interlayer selection, and thickness of each layer were varied to achieve tailorable physical properties and enhance coupling. The hyperbolic behavior can be tailored by varying the thickness of the ZnO-Ni layer. The magnetic anisotropy of the films, including coercivity and saturation magnetization, can be tuned by the number of film layers. Plus, the ferroelectric behavior can be tuned by the LNO layer thickness. This study demonstrates the growth of a new complex hybrid metamaterial system and its potential in plasmonics, integrated photonics, acoustic sensing, and data storage applications.