Dielectric properties of 〈001〉 -Oriented Ba _0.6Sr _0.4TiO ₃ thin films on polycrystalline metal tapes using biaxially oriented MgO/γ-Al ₂O ₃ buffer layers

We report the growth of 〈001〉 -oriented Ba0.6 Sr0.4 TiO3 (BST) thin films on polycrystalline Ni-alloy tapes by pulsed laser deposition using biaxially oriented, ion-beam-assisted deposited (IBAD) MgO and γ- Al2 O3 buffer layers. Dielectric constant values of our BST films were up to ∼85% of those in the epitaxial films prepared under similar conditions on single-crystal MgO substrates. No significant dispersion of the dielectric constant was observed for frequencies from 100 Hz to 1 MHz. These results demonstrate the versatility of using IBAD-textured MgO and γ- Al2 O3 buffer layers to integrate highly oriented good-quality BST films with nonsingle-crystalline substrates.