Effects of LaNiO buffer layer on improving the dielectric properties of barium strontium titanate thin films on stainless steel substrates.

LaNiO (LNO) buffer layer was introduced into barium strontium titanate (BST) thin films deposited on stainless steel (SS) substrates by the sol-gel technique. Results show that the crystallization temperature of BST thin films is decreased from 750 to 720 °C by introducing LNO conducting oxide layer. Simultaneously, the suffered thermal stress for BST films is depressed as SS is a 'compressive' substrate. Furthermore, the dielectric loss is notably decreased especially at 10-10 Hz, and the tunability is improved from 24.0 to 26.6 % under the field of 300 kV/cm, because the strain is reduced as characterized by the XRD and Raman spectra. The leakage current density of BST thin films is also significantly decreased by LNO layer, and its mechanism is analyzed. Such results imply that it is worthwhile to introduce LNO buffer layer for BST films on metal substrates to improve their dielectric properties by reducing the misfit strains, especially for 'compressive' substrates. Graphical Abstract: [ABSTRACT FROM AUTHOR]