Properties of SrBi₂Ta_0.8Nb_1.2O₉ thin films deposited by plasma-assisted pulsed-laser deposition

A significant effect of the introduction of O2 -plasma discharge during pulsed laser ablative deposition of Sr Bi2 Ta0.8 Nb1.2 O9 (SBTN) films on improving the crystallite orientation, ferroelectric, and optical properties has been described. Plasma-excitation potential, applied at an auxiliary-ring electrode placed near the substrate, has a profound effect on surface morphology, crystallite orientation, remnant polarization, and optical constants. Compared with no plasma assist, the films have an additional strong (008) and (200) and an approximate 32% multiplication in remnant polarization. The refractive index (n∼2.27) with plasma is greater than the corresponding values (n∼2.16) of no plasma. Clearly, the presence of O2 plasma assists in the growth of SBTN films, which display much improved ferroelectric and optical properties.