Enhanced ferroelectric properties of Mg doped (Ba,Sr)TiO3 thick films grown on (001) SrTiO3 substrates

Highly (001)-oriented 1 mol% Mg doped (Ba0.67,Sr0.33)TiO3 (BST) films with a thickness of 1.25 μm were grown on (110) SrRuO3/(001) SrTiO3 substrates by pulsed laser deposition. X-ray diffraction measurements reveal that the BST thick films have very high crystalline quality, and have a distorted lattice with a large tetragonality a/c = 1.012. The BST thick films have a remanent polarization (Pr) value as large as 10.1 μC/cm2 and a coercive electric field (Ec) value of 65.0 kV/cm. The films possess dielectric constant and loss values of εr = 385.36 and tgδ = 0.038 at 1 kHz and room temperature. The leakage currents of the films are on the order of 10− 5 A/cm2 at ± 150 kV/cm. The mechanism for enhancing electric properties of the Mg doped BST films was also discussed.