Enhanced tunability of sandwich-like structural barium strontium titanate thin films on stainless steel substrates

摘要: Barium strontium titanate (BST) thin films deposited on stainless steel (SS) substrates can be expected for their potential applications in MEMS-structure tunable microwave devices. In this paper, two sandwich-like structures with varied average Ba/Sr ratio of BST films, Ba0.6Sr0.4TiO3 layer the middle or at ends, LaNiO3 buffered SS were fabricated by sol–gel technique, and meanwhile theoretically carried out via a modified phenomenological model. Results show that dielectric constant tunability such tailored structures. When is unchanged, structure smaller lattice parameter than top/bottom achieve larger resulting from its compressive misfit strain, which has been qualitatively characterized X-ray diffraction Raman spectra. Especially, largest reaches 30 % under electric field 300 kV cm−1 locating Ba0.4Sr0.6TiO3 layers ends. Furthermore, experimental constants tunabilities are good agreement calculated data, instructing properties unchanged changing to adjust strain each uniform layer. This implies multilayer also designed theory.