Evaluation of Strain-Dependent Dielectric Properties in BaTiO3 ∕ LaNiO3 and ( Ba , Sr ) TiO3 ∕ LaNiO3 Artificial Superlattice Films on LaNiO3-Coated SrTiO3 Substrates

Abstract

We formed strained artificial superlattices of and on -coated (001) substrates by dual-gun radio-frequency magnetron sputtering. The (00L) crystal truncation rod intensity profiles confirm the formation of a superlattice structure. The BTO (or BST) sublayer in the artificial superlattice is under biaxial compressive stress whereas the LNO sublayer is under biaxial tensile stress. Both and superlattices of total thickness exhibit some degree of strain relaxation, even though the modulation length is less than the critical value to generate misfit dislocations. These and artificial superlattices show a dielectric constant significantly enhanced relative to BTO and BST single layers of the same effective thickness. From a macroscopic point of view, the strain in the superlattice structure contributes significantly to the dielectric enhancement.