Structure and dielectric properties of barium strontium titanate ferroelectric thin film prepared by DC micro-arc oxidation

Barium–strontium titanate (BST) ferroelectric thin film was fabricated on Ti substrates by micro-arc oxidation (MAO) in an aqueous solution consisting of 0.6 mol/L Ba(OH)${}_2$·8H2${}_2$O and 0.4 mol/L Sr(OH)${}_2$·8H${}_2$O. The phase composition, elements distribution, dielectric and ferroelectric properties of the BST thin film were characterized. The results show that the BST film is mainly composed of Ba${}_x$Sr${}_{(1-x)}$TiO${}_3$ phase. The Ba, Sr, Ti and O elements are generally uniformly distributed across the film, and the local fluctuation of elements distribution may be caused by MAO holes in the membrane. The BST film is mainly deposited through an electrophoretic process. The dielectric constant of the BST thin film is about 283 measured at 1 kHz, and the film has ferroelectric property at room temperature because of the misfit strain in the film.