Strain and property tuning of the 3D framed epitaxial nanocomposite thin films via interlayer thickness variation

This work demonstrates the growth of three-dimensional (3D) ZnO-framed La _0.7 Sr _0.3 MnO ₃ (LSMO)-ZnO heteroepitaxial thin films in a vertically aligned nanocomposite (VAN) form on SrTiO ₃ (STO) substrates. Such 3D framed structures are formed by interlayering pure ZnO layers in LSMO-ZnO VAN thin films to thus achieve a ZnO-framed nanocomposite structure. Tailoring the thickness of the ZnO interlayer enables fine-tuning of the overall strain state of the two phases and thus leads to the tuning of the physical properties, such as the metal-insulator transition temperature, and magnetotransport properties. The optimum thickness of the ZnO interlayer is determined to be ∼2 nm to obtain a maximum magnetoresistance of 31% by a combined strain tuning and magnetoresistance tunneling effect. This work demonstrates effective strain tuning using the 3D framed design and provides a comprehensive perspective on the strain- and property-tuning using 3D nanocomposite frameworks.