Integration of functional thin films with a multiferroic property on flexible substrates has piqued tremendous research interest and device potential for flexible electronics. In this work, self-assembled BaTiO3–Fe vertically aligned nanocomposite (VAN) thin films have been integrated on mica substrates using pulsed laser deposition. Different buffer layers have been explored to facilitate VAN growth. The anisotropic ferromagnetic property and room temperature ferroelectric property have been achieved in the films. The bending test up to 1000 cycles signifies the mechanical stability of the physical properties. This work paves an avenue to integrate multiferroic oxide–metal nanocomposites for future flexible device integration.

Tetragonal tungsten bronze (TTB) materials are one of the most promising classes of materials for ferroelectric and nonlinear optical devices, owing to their very unique noncentrosymmetric crystal structure. In this work, a new TTB phase of LiNb6Ba5Ti4O30 (LNBTO) has been discovered and studied. A small amount of a secondary phase, LiTiO2 (LTO), has been incorporated as nanopillars that are vertically embedded in the LNBTO matrix. The new multifunctional nanocomposite thin film presents exotic highly anisotropic microstructure and properties, e.g., strong ferroelectricity, high optical transparency, anisotropic dielectric function, and strong optical nonlinearity evidenced by the second harmonic generation results. An optical waveguide structure based on the stacks of α-Si on SiO2/LNBTO–LTO has been fabricated, exhibiting low optical dispersion with an optimized evanescent field staying in the LNBTO–LTO active layer. This work highlights the combination of new TTB material designs and vertically aligned nanocomposite structures for further enhanced anisotropic and nonlinear properties.