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Abstract Manufacture and characterizations of perovskite-mica van der Waals epitaxy heterostructures are a critical step to realize the application of flexible devices. However, the fabrication and investigation of the van der Waals epitaxy architectures grown on mica substrates are mainly limited to (111)-oriented perovskite functional oxide thin films up to now and buffer layers are highly needed. In this work, we directly grew La 0.7 Sr 0.3 MnO 3 (LSMO) thin films on mica substrates without using any buffer layer. By the characterizations of x-ray diffractometer and scanning transmission electron microscopy, we demonstrate the epitaxial growth of the (110)-oriented LSMO thin film on the mica substrate. The LSMO thin film grown on the mica substrate via van der Waals epitaxy adopts domain matching epitaxy instead of conventional lattice matching epitaxy. Two kinds of domain matching relationships between the LSMO thin film and mica substrate are sketched by Visualization for Electronic and STructural Analysis software and discussed. A decent ferromagnetism retains in the (110)-oriented LSMO thin film. Our work demonstrates a new pathway to fabricate (110)-oriented functional oxide thin films on flexible mica substrates directly. 

Due to environmental concerns and the increasing drive towards miniaturization of electronic circuits and devices, lead-free ferroelectric films with low leakage current and robust ferroelectric and piezoelectric properties are highly desired. The preferred alternative, BaTiO 3 , is non-toxic and has ferroelectric properties, but its high leakage current, poor ferroelectricity and piezoelectricity and low Curie temperature of ∼130 °C in thin film form are obstacles for high-temperature practical applications. Here, we report that a negative-pressure-driven enhancement of ferroelectric Curie temperature and effective piezoelectric coefficient are achieved in (111)-oriented BaTiO 3 nanocomposite films. The enhanced ferroelectric and piezoelectric properties in the emergent monoclinic BaTiO 3 are attributed to the sharp vertical interface and 3D tensile strain that develops upon interspersing stiff and self-assembled vertical Sm 2 O 3 nanopillars through the film thickness. Our work also demonstrates that fabricating oxide films through (111)-oriented epitaxy opens up new avenues for the creation of new phase components and exploration of novel functionalities for developing oxide quantum electronic devices.