Enhanced dielectric responses of Ba0.6Sr0.4TiO3 thin films onto BaxSr1−xTiO3-buffered stainless steel substrates

Abstract

Misfit strain, lattice parameter, polarization, permittivity, and tunability of Ba[Formula: see text]Sr[Formula: see text]TiO3 thin films onto Ba[Formula: see text]Sr1−xTiO3-buffered stainless steel (SS) substrates are computed via a modified phenomenological model. When the Ba/Sr ratio of Ba[Formula: see text]Sr1−xTiO3 buffer layer grows, the permittivity and tunability first increase and then decrease with the maximum at [Formula: see text] = 0.75. The highest tunability of such films prepared by the sol-gel technique can reach 32.5% at the electric field of 320 kV/cm when [Formula: see text] = 0.8. The strains are qualitatively analyzed through combining XRD, Raman, and theoretical calculation. The computed data are generally supported by experimental lattice parameters, permittivities, and tunabilities, which show that polycrystalline BST thin films with smaller compressive strain obtain higher dielectric response, and that inserting buffer layer could regulate the strains and dielectric properties of BST thin films.