Abstract:We formed strained artificial superlattices of BaTiO3/LaNiO3(BTO/LNO) and (Ba0.48Sr0.52)TiO3/LaNiO3(BST/LNO) on LaNiO3-coated SrTiO3 (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 BTO/LNO and BST/LNO superlattices of total thickness ~60 nm exhibit some degree of strain relaxation, even though the modulation length is less than the critical value to generate misfit dislocations. These BTO/LNO and BST/LNO 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.
