PLD Epitaxial Thin-Film BaTiO₃ on MgO - Dielectric and Electro-Optic Properties

The study demonstrates high-quality pulsed-laser-deposited (PLD) barium titanate (BTO) thin-films on a magnesium oxide substrate. The frequency response of the relative permittivity (dielectric constant) and the linear electro-optical coefficient (Pockels coefficient) are measured. At 0.2 GHz, the Pockels coefficient is fitted to be r(42) approximate to 1030 pm V-1. It decreases to approximate to 390 pm V-1 at 10 GHz after which it remains constant up to 70 GHz. The unbiased BTO permittivity is measured to be epsilon(a) approximate to 7600 at 0.2 GHz, dropping to approximate to 1100 at 67 GHz, while the biased BTO had a permittivity epsilon(a) approximate to 2000 at 0.2 GHz, dropping to approximate to 500 at 67 GHz. These results fill an important experimental characterization gap for high-speed BTO applications and show the high quality of PLD-grown BTO films. Lastly, the material's crystalline quality is characterized and the domain distribution is imaged. The findings enable the design and fabrication of a new generation of BTO-based components for sensing and communications.