Dielectric properties of < 001 >-oriented Ba_(0.6)Sr_(0.4)TiO_3 thin films on polycrystalline metal tapes using biaxially oriented MgO/γ-Al_2O_3 buffer layers

摘要

We report the growth of < 001 >-oriented Ba_(0.6)Sr_(0.4)TiO_3 (BST) thin films on polycrystalline Ni-alloy tapes by pulsed laser deposition using biaxially oriented, ion-beam-assisted deposited (IBAD) MgO and γ-Al_2O_3 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-Al_2O_3 buffer layers to integrate highly oriented good-quality BST films with nonsingle-crystalline substrates.